[llvm] 0915825 - [ThinLTO] Allow usage of all hardware threads in the system
Hans Wennborg via llvm-commits
llvm-commits at lists.llvm.org
Mon Apr 6 09:52:23 PDT 2020
This broke some LLD ThinLTO tests in 32-bit Windows builds. Can you take a look?
I wonder if it's simply running out of the 32-bit address space when
running so many threads (I have a lot of cores on my machine)..
See the example output below:
C:\src\llvm.monorepo>ninja -C build.32 lld opt llvm-nm && python
build.32\bin\llvm-lit.py -v lld\test\COFF\thinlto.ll
ninja: Entering directory `build.32'
ninja: no work to do.
llvm-lit.py: C:/src/llvm.monorepo/llvm\utils\lit\lit\llvm\config.py:342:
note: using ld.lld: c:\src\llvm.monorepo\build.32\bin\ld.lld.exe
llvm-lit.py: C:/src/llvm.monorepo/llvm\utils\lit\lit\llvm\config.py:342:
note: using lld-link: c:\src\llvm.monorepo\build.32\bin\lld-link.exe
llvm-lit.py: C:/src/llvm.monorepo/llvm\utils\lit\lit\llvm\config.py:342:
note: using ld64.lld: c:\src\llvm.monorepo\build.32\bin\ld64.lld.exe
llvm-lit.py: C:/src/llvm.monorepo/llvm\utils\lit\lit\llvm\config.py:342:
note: using wasm-ld: c:\src\llvm.monorepo\build.32\bin\wasm-ld.exe
-- Testing: 1 tests, 1 workers --
FAIL: lld :: COFF/thinlto.ll (1 of 1)
******************** TEST 'lld :: COFF/thinlto.ll' FAILED ********************
Script:
--
: 'RUN: at line 2'; rm -fr
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto
: 'RUN: at line 3'; mkdir
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto
: 'RUN: at line 4'; c:\src\llvm.monorepo\build.32\bin\opt.exe
-thinlto-bc -o C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj
C:\src\llvm.monorepo\lld\test\COFF\thinlto.ll
: 'RUN: at line 5'; c:\src\llvm.monorepo\build.32\bin\opt.exe
-thinlto-bc -o C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj
C:\src\llvm.monorepo\lld\test\COFF/Inputs/lto-dep.ll
: 'RUN: at line 6'; c:\src\llvm.monorepo\build.32\bin\lld-link.exe
/lldsavetemps /out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe
/entry:main /subsystem:console
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj
: 'RUN: at line 7'; c:\src\llvm.monorepo\build.32\bin\llvm-nm.exe
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe1.lto.obj
| c:\src\llvm.monorepo\build.32\bin\filecheck.exe
C:\src\llvm.monorepo\lld\test\COFF\thinlto.ll
: 'RUN: at line 10'; c:\src\llvm.monorepo\build.32\bin\lld-link.exe
/lldsavetemps /out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe
/entry:main /subsystem:console
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj
/opt:lldltojobs=1
: 'RUN: at line 11'; c:\src\llvm.monorepo\build.32\bin\llvm-nm.exe
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe1.lto.obj
| c:\src\llvm.monorepo\build.32\bin\filecheck.exe
C:\src\llvm.monorepo\lld\test\COFF\thinlto.ll
: 'RUN: at line 12'; c:\src\llvm.monorepo\build.32\bin\lld-link.exe
/lldsavetemps /out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe
/entry:main /subsystem:console
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj
/opt:lldltojobs=all
: 'RUN: at line 13'; c:\src\llvm.monorepo\build.32\bin\llvm-nm.exe
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe1.lto.obj
| c:\src\llvm.monorepo\build.32\bin\filecheck.exe
C:\src\llvm.monorepo\lld\test\COFF\thinlto.ll
: 'RUN: at line 14'; c:\src\llvm.monorepo\build.32\bin\lld-link.exe
/lldsavetemps /out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe
/entry:main /subsystem:console
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj
/opt:lldltojobs=1000
: 'RUN: at line 15'; c:\src\llvm.monorepo\build.32\bin\llvm-nm.exe
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe1.lto.obj
| c:\src\llvm.monorepo\build.32\bin\filecheck.exe
C:\src\llvm.monorepo\lld\test\COFF\thinlto.ll
: 'RUN: at line 16'; not
c:\src\llvm.monorepo\build.32\bin\lld-link.exe /lldsavetemps
/out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe
/entry:main /subsystem:console
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj
/opt:lldltojobs=foo 2>&1 |
c:\src\llvm.monorepo\build.32\bin\filecheck.exe
C:\src\llvm.monorepo\lld\test\COFF\thinlto.ll --check-prefix=BAD-JOBS
: 'RUN: at line 21'; c:\src\llvm.monorepo\build.32\bin\lld-link.exe
/lib C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj
/out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output\thinlto.ll.tmp.lib
: 'RUN: at line 22'; c:\src\llvm.monorepo\build.32\bin\lld-link.exe
/lldsavetemps /out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output\thinlto.ll.tmp.exe
/entry:main /subsystem:console
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output\thinlto.ll.tmp.lib
--
Exit Code: -529697949
Command Output (stdout):
--
$ ":" "RUN: at line 2"
$ "rm" "-fr" "C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto"
$ ":" "RUN: at line 3"
$ "mkdir" "C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto"
$ ":" "RUN: at line 4"
$ "c:\src\llvm.monorepo\build.32\bin\opt.exe" "-thinlto-bc" "-o"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj"
"C:\src\llvm.monorepo\lld\test\COFF\thinlto.ll"
$ ":" "RUN: at line 5"
$ "c:\src\llvm.monorepo\build.32\bin\opt.exe" "-thinlto-bc" "-o"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj"
"C:\src\llvm.monorepo\lld\test\COFF/Inputs/lto-dep.ll"
$ ":" "RUN: at line 6"
$ "c:\src\llvm.monorepo\build.32\bin\lld-link.exe" "/lldsavetemps"
"/out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe"
"/entry:main" "/subsystem:console"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj"
$ ":" "RUN: at line 7"
$ "c:\src\llvm.monorepo\build.32\bin\llvm-nm.exe"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe1.lto.obj"
$ "c:\src\llvm.monorepo\build.32\bin\filecheck.exe"
"C:\src\llvm.monorepo\lld\test\COFF\thinlto.ll"
$ ":" "RUN: at line 10"
$ "c:\src\llvm.monorepo\build.32\bin\lld-link.exe" "/lldsavetemps"
"/out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe"
"/entry:main" "/subsystem:console"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj"
"/opt:lldltojobs=1"
$ ":" "RUN: at line 11"
$ "c:\src\llvm.monorepo\build.32\bin\llvm-nm.exe"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe1.lto.obj"
$ "c:\src\llvm.monorepo\build.32\bin\filecheck.exe"
"C:\src\llvm.monorepo\lld\test\COFF\thinlto.ll"
$ ":" "RUN: at line 12"
$ "c:\src\llvm.monorepo\build.32\bin\lld-link.exe" "/lldsavetemps"
"/out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe"
"/entry:main" "/subsystem:console"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj"
"/opt:lldltojobs=all"
$ ":" "RUN: at line 13"
$ "c:\src\llvm.monorepo\build.32\bin\llvm-nm.exe"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe1.lto.obj"
$ "c:\src\llvm.monorepo\build.32\bin\filecheck.exe"
"C:\src\llvm.monorepo\lld\test\COFF\thinlto.ll"
$ ":" "RUN: at line 14"
$ "c:\src\llvm.monorepo\build.32\bin\lld-link.exe" "/lldsavetemps"
"/out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe"
"/entry:main" "/subsystem:console"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj"
"C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj"
"/opt:lldltojobs=1000"
# command stderr:
PLEASE submit a bug report to https://bugs.llvm.org/ and include the
crash backtrace.
Stack dump:
0. Program arguments:
c:\src\llvm.monorepo\build.32\bin\lld-link.exe /lldsavetemps
/out:C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.exe
/entry:main /subsystem:console
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/main.obj
C:\src\llvm.monorepo\build.32\tools\lld\test\COFF\Output/thinlto/foo.obj
/opt:lldltojobs=1000
0x73F647B2 (0xE06D7363 0x00000001 0x00000003 0x04FEE500),
RaiseException() + 0x62 bytes(s)
0x72CC7A36 (0x04FEE524 0x6AA43570 0x004ED908 0x004B7A50),
_CxxThrowException() + 0x66 bytes(s)
0x6AA183F6 (0x00000006 0x004B7A40 0x04FEE680 0x004B7A40),
?_Throw_Cpp_error at std@@YAXH at Z() + 0x36 bytes(s)
0x02BA8A79 (0x000003E8 0x00000001 0x004B7A40 0x04FEE680)
0x01E86C79 (0x00000188 0x00000190 0x0046035C 0x04FEE664)
0x7740CFB7 (0x04FEE680 0x00000000 0x00000188 0x00000000),
RtlAllocateHeap() + 0x307 bytes(s)
0x741CF1F6 (0x00000188 0x004B6DD8 0x01E85E3D 0x00000000),
_malloc_base() + 0x26 bytes(s)
0x02B83056 (0x00000000 0x00000000 0x004935D8 0x02BF3280)
0x01E85E3D (0x00000000 0x00000000 0x04FEE6FC 0x02B83077)
0x741CDAE8 (0x00000000 0x04FEE6D8 0x01E922FE 0x00000000), free() + 0x18 bytes(s)
0x02B83077 (0x00000000 0x00000000 0x00000000 0x004935D8)
0x01E922FE (0x04FEE760 0x004B6DB4 0x004B69B0 0x004B6DD8)
error: command failed with exit status: 0xe06d7363
--
On Fri, Mar 27, 2020 at 3:21 PM Alexandre Ganea via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
>
>
> Author: Alexandre Ganea
> Date: 2020-03-27T10:20:58-04:00
> New Revision: 09158252f777c2e2f06a86b154c44abcbcf9bb74
>
> URL: https://github.com/llvm/llvm-project/commit/09158252f777c2e2f06a86b154c44abcbcf9bb74
> DIFF: https://github.com/llvm/llvm-project/commit/09158252f777c2e2f06a86b154c44abcbcf9bb74.diff
>
> LOG: [ThinLTO] Allow usage of all hardware threads in the system
>
> Before this patch, it wasn't possible to extend the ThinLTO threads to all SMT/CMT threads in the system. Only one thread per core was allowed, instructed by usage of llvm::heavyweight_hardware_concurrency() in the ThinLTO code. Any number passed to the LLD flag /opt:lldltojobs=..., or any other ThinLTO-specific flag, was previously interpreted in the context of llvm::heavyweight_hardware_concurrency(), which means SMT disabled.
>
> One can now say in LLD:
> /opt:lldltojobs=0 -- Use one std::thread / hardware core in the system (no SMT). Default value if flag not specified.
> /opt:lldltojobs=N -- Limit usage to N threads, regardless of usage of heavyweight_hardware_concurrency().
> /opt:lldltojobs=all -- Use all hardware threads in the system. Equivalent to /opt:lldltojobs=$(nproc) on Linux and /opt:lldltojobs=%NUMBER_OF_PROCESSORS% on Windows. When an affinity mask is set for the process, threads will be created only for the cores selected by the mask.
>
> When N > number-of-hardware-threads-in-the-system, the threads in the thread pool will be dispatched equally on all CPU sockets (tested only on Windows).
> When N <= number-of-hardware-threads-on-a-CPU-socket, the threads will remain on the CPU socket where the process started (only on Windows).
>
> Differential Revision: https://reviews.llvm.org/D75153
>
> Added:
>
>
> Modified:
> clang/lib/Driver/ToolChains/CommonArgs.cpp
> clang/lib/Driver/ToolChains/CommonArgs.h
> clang/lib/Driver/ToolChains/Darwin.cpp
> lld/COFF/Config.h
> lld/COFF/Driver.cpp
> lld/COFF/LTO.cpp
> lld/ELF/Config.h
> lld/ELF/Driver.cpp
> lld/ELF/LTO.cpp
> lld/test/COFF/thinlto.ll
> lld/test/ELF/basic.s
> lld/test/ELF/lto/thinlto.ll
> lld/test/wasm/lto/thinlto.ll
> lld/wasm/Config.h
> lld/wasm/Driver.cpp
> lld/wasm/LTO.cpp
> llvm/include/llvm/LTO/LTO.h
> llvm/include/llvm/Support/Threading.h
> llvm/lib/LTO/LTO.cpp
> llvm/lib/Support/Threading.cpp
> llvm/lib/Support/Unix/Threading.inc
> llvm/lib/Support/Windows/Threading.inc
> llvm/tools/gold/gold-plugin.cpp
> llvm/tools/llvm-lto2/llvm-lto2.cpp
>
> Removed:
>
>
>
> ################################################################################
> diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
> index 51b2e5f3c34d..303ced52454c 100644
> --- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
> +++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
> @@ -50,6 +50,7 @@
> #include "llvm/Support/Program.h"
> #include "llvm/Support/ScopedPrinter.h"
> #include "llvm/Support/TargetParser.h"
> +#include "llvm/Support/Threading.h"
> #include "llvm/Support/VirtualFileSystem.h"
> #include "llvm/Support/YAMLParser.h"
>
> @@ -338,14 +339,14 @@ std::string tools::getCPUName(const ArgList &Args, const llvm::Triple &T,
> }
> }
>
> -unsigned tools::getLTOParallelism(const ArgList &Args, const Driver &D) {
> - unsigned Parallelism = 0;
> +llvm::StringRef tools::getLTOParallelism(const ArgList &Args, const Driver &D) {
> Arg *LtoJobsArg = Args.getLastArg(options::OPT_flto_jobs_EQ);
> - if (LtoJobsArg &&
> - StringRef(LtoJobsArg->getValue()).getAsInteger(10, Parallelism))
> - D.Diag(diag::err_drv_invalid_int_value) << LtoJobsArg->getAsString(Args)
> - << LtoJobsArg->getValue();
> - return Parallelism;
> + if (!LtoJobsArg)
> + return {};
> + if (!llvm::get_threadpool_strategy(LtoJobsArg->getValue()))
> + D.Diag(diag::err_drv_invalid_int_value)
> + << LtoJobsArg->getAsString(Args) << LtoJobsArg->getValue();
> + return LtoJobsArg->getValue();
> }
>
> // CloudABI uses -ffunction-sections and -fdata-sections by default.
> @@ -410,7 +411,8 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args,
> if (IsThinLTO)
> CmdArgs.push_back("-plugin-opt=thinlto");
>
> - if (unsigned Parallelism = getLTOParallelism(Args, ToolChain.getDriver()))
> + StringRef Parallelism = getLTOParallelism(Args, ToolChain.getDriver());
> + if (!Parallelism.empty())
> CmdArgs.push_back(
> Args.MakeArgString("-plugin-opt=jobs=" + Twine(Parallelism)));
>
>
> diff --git a/clang/lib/Driver/ToolChains/CommonArgs.h b/clang/lib/Driver/ToolChains/CommonArgs.h
> index 984f3ee98af1..c94b2b828c9b 100644
> --- a/clang/lib/Driver/ToolChains/CommonArgs.h
> +++ b/clang/lib/Driver/ToolChains/CommonArgs.h
> @@ -88,7 +88,8 @@ llvm::opt::Arg *getLastProfileSampleUseArg(const llvm::opt::ArgList &Args);
>
> bool isObjCAutoRefCount(const llvm::opt::ArgList &Args);
>
> -unsigned getLTOParallelism(const llvm::opt::ArgList &Args, const Driver &D);
> +llvm::StringRef getLTOParallelism(const llvm::opt::ArgList &Args,
> + const Driver &D);
>
> bool areOptimizationsEnabled(const llvm::opt::ArgList &Args);
>
>
> diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
> index d1aec649cdc7..451d0d206d07 100644
> --- a/clang/lib/Driver/ToolChains/Darwin.cpp
> +++ b/clang/lib/Driver/ToolChains/Darwin.cpp
> @@ -23,6 +23,7 @@
> #include "llvm/Support/Path.h"
> #include "llvm/Support/ScopedPrinter.h"
> #include "llvm/Support/TargetParser.h"
> +#include "llvm/Support/Threading.h"
> #include "llvm/Support/VirtualFileSystem.h"
> #include <cstdlib> // ::getenv
>
> @@ -605,10 +606,12 @@ void darwin::Linker::ConstructJob(Compilation &C, const JobAction &JA,
>
> getMachOToolChain().addProfileRTLibs(Args, CmdArgs);
>
> - if (unsigned Parallelism =
> - getLTOParallelism(Args, getToolChain().getDriver())) {
> + StringRef Parallelism = getLTOParallelism(Args, getToolChain().getDriver());
> + if (!Parallelism.empty()) {
> CmdArgs.push_back("-mllvm");
> - CmdArgs.push_back(Args.MakeArgString("-threads=" + Twine(Parallelism)));
> + unsigned NumThreads =
> + llvm::get_threadpool_strategy(Parallelism)->compute_thread_count();
> + CmdArgs.push_back(Args.MakeArgString("-threads=" + Twine(NumThreads)));
> }
>
> if (getToolChain().ShouldLinkCXXStdlib(Args))
>
> diff --git a/lld/COFF/Config.h b/lld/COFF/Config.h
> index e376ea51f133..93b732ea6821 100644
> --- a/lld/COFF/Config.h
> +++ b/lld/COFF/Config.h
> @@ -144,7 +144,7 @@ struct Configuration {
> unsigned ltoo = 2;
>
> // Used for /opt:lldltojobs=N
> - unsigned thinLTOJobs = 0;
> + std::string thinLTOJobs;
> // Used for /opt:lldltopartitions=N
> unsigned ltoPartitions = 1;
>
>
> diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
> index 8b3ba1cdf24b..7d99f798a322 100644
> --- a/lld/COFF/Driver.cpp
> +++ b/lld/COFF/Driver.cpp
> @@ -1417,9 +1417,9 @@ void LinkerDriver::link(ArrayRef<const char *> argsArr) {
> error("/opt:lldlto: invalid optimization level: " + optLevel);
> } else if (s.startswith("lldltojobs=")) {
> StringRef jobs = s.substr(11);
> - if (jobs.getAsInteger(10, config->thinLTOJobs) ||
> - config->thinLTOJobs == 0)
> + if (!get_threadpool_strategy(jobs))
> error("/opt:lldltojobs: invalid job count: " + jobs);
> + config->thinLTOJobs = jobs.str();
> } else if (s.startswith("lldltopartitions=")) {
> StringRef n = s.substr(17);
> if (n.getAsInteger(10, config->ltoPartitions) ||
>
> diff --git a/lld/COFF/LTO.cpp b/lld/COFF/LTO.cpp
> index 247331b16928..94906e500593 100644
> --- a/lld/COFF/LTO.cpp
> +++ b/lld/COFF/LTO.cpp
> @@ -101,8 +101,9 @@ BitcodeCompiler::BitcodeCompiler() {
> std::string(config->thinLTOPrefixReplace.first),
> std::string(config->thinLTOPrefixReplace.second),
> config->thinLTOEmitImportsFiles, indexFile.get(), OnIndexWrite);
> - } else if (config->thinLTOJobs != 0) {
> - backend = lto::createInProcessThinBackend(config->thinLTOJobs);
> + } else {
> + backend = lto::createInProcessThinBackend(
> + llvm::heavyweight_hardware_concurrency(config->thinLTOJobs));
> }
>
> ltoObj = std::make_unique<lto::LTO>(createConfig(), backend,
>
> diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h
> index 9f9f0d696f63..0263708634cb 100644
> --- a/lld/ELF/Config.h
> +++ b/lld/ELF/Config.h
> @@ -246,7 +246,7 @@ struct Configuration {
> unsigned ltoPartitions;
> unsigned ltoo;
> unsigned optimize;
> - unsigned thinLTOJobs;
> + StringRef thinLTOJobs;
> unsigned timeTraceGranularity;
> int32_t splitStackAdjustSize;
>
>
> diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
> index f9a1340e25d3..95276cd33420 100644
> --- a/lld/ELF/Driver.cpp
> +++ b/lld/ELF/Driver.cpp
> @@ -974,7 +974,7 @@ static void readConfigs(opt::InputArgList &args) {
> config->thinLTOIndexOnly = args.hasArg(OPT_thinlto_index_only) ||
> args.hasArg(OPT_thinlto_index_only_eq);
> config->thinLTOIndexOnlyArg = args.getLastArgValue(OPT_thinlto_index_only_eq);
> - config->thinLTOJobs = args::getInteger(args, OPT_thinlto_jobs, -1u);
> + config->thinLTOJobs = args.getLastArgValue(OPT_thinlto_jobs);
> config->thinLTOObjectSuffixReplace =
> getOldNewOptions(args, OPT_thinlto_object_suffix_replace_eq);
> config->thinLTOPrefixReplace =
> @@ -1040,8 +1040,8 @@ static void readConfigs(opt::InputArgList &args) {
> error("invalid optimization level for LTO: " + Twine(config->ltoo));
> if (config->ltoPartitions == 0)
> error("--lto-partitions: number of threads must be > 0");
> - if (config->thinLTOJobs == 0)
> - error("--thinlto-jobs: number of threads must be > 0");
> + if (!get_threadpool_strategy(config->thinLTOJobs))
> + error("--thinlto-jobs: invalid job count: " + config->thinLTOJobs);
>
> if (config->splitStackAdjustSize < 0)
> error("--split-stack-adjust-size: size must be >= 0");
>
> diff --git a/lld/ELF/LTO.cpp b/lld/ELF/LTO.cpp
> index ba943283706a..f4e04a82f0c2 100644
> --- a/lld/ELF/LTO.cpp
> +++ b/lld/ELF/LTO.cpp
> @@ -146,8 +146,9 @@ BitcodeCompiler::BitcodeCompiler() {
> std::string(config->thinLTOPrefixReplace.first),
> std::string(config->thinLTOPrefixReplace.second),
> config->thinLTOEmitImportsFiles, indexFile.get(), onIndexWrite);
> - } else if (config->thinLTOJobs != -1U) {
> - backend = lto::createInProcessThinBackend(config->thinLTOJobs);
> + } else {
> + backend = lto::createInProcessThinBackend(
> + llvm::heavyweight_hardware_concurrency(config->thinLTOJobs));
> }
>
> ltoObj = std::make_unique<lto::LTO>(createConfig(), backend,
>
> diff --git a/lld/test/COFF/thinlto.ll b/lld/test/COFF/thinlto.ll
> index 517be330c710..a8390721cc42 100644
> --- a/lld/test/COFF/thinlto.ll
> +++ b/lld/test/COFF/thinlto.ll
> @@ -6,6 +6,16 @@
> ; RUN: lld-link /lldsavetemps /out:%T/thinlto/main.exe /entry:main /subsystem:console %T/thinlto/main.obj %T/thinlto/foo.obj
> ; RUN: llvm-nm %T/thinlto/main.exe1.lto.obj | FileCheck %s
>
> +; Test various possible options for /opt:lldltojobs
> +; RUN: lld-link /lldsavetemps /out:%T/thinlto/main.exe /entry:main /subsystem:console %T/thinlto/main.obj %T/thinlto/foo.obj /opt:lldltojobs=1
> +; RUN: llvm-nm %T/thinlto/main.exe1.lto.obj | FileCheck %s
> +; RUN: lld-link /lldsavetemps /out:%T/thinlto/main.exe /entry:main /subsystem:console %T/thinlto/main.obj %T/thinlto/foo.obj /opt:lldltojobs=all
> +; RUN: llvm-nm %T/thinlto/main.exe1.lto.obj | FileCheck %s
> +; RUN: lld-link /lldsavetemps /out:%T/thinlto/main.exe /entry:main /subsystem:console %T/thinlto/main.obj %T/thinlto/foo.obj /opt:lldltojobs=1000
> +; RUN: llvm-nm %T/thinlto/main.exe1.lto.obj | FileCheck %s
> +; RUN: not lld-link /lldsavetemps /out:%T/thinlto/main.exe /entry:main /subsystem:console %T/thinlto/main.obj %T/thinlto/foo.obj /opt:lldltojobs=foo 2>&1 | FileCheck %s --check-prefix=BAD-JOBS
> +; BAD-JOBS: error: /opt:lldltojobs: invalid job count: foo
> +
> ; This command will store full path to foo.obj in the archive %t.lib
> ; Check that /lldsavetemps is still usable in such case.
> ; RUN: lld-link /lib %T/thinlto/foo.obj /out:%t.lib
>
> diff --git a/lld/test/ELF/basic.s b/lld/test/ELF/basic.s
> index b0509a2dc123..5300c6efa2ef 100644
> --- a/lld/test/ELF/basic.s
> +++ b/lld/test/ELF/basic.s
> @@ -249,9 +249,21 @@ _start:
> # RUN: not ld.lld %t --plugin-opt=lto-partitions=0 2>&1 | FileCheck --check-prefix=NOTHREADS %s
> # NOTHREADS: --lto-partitions: number of threads must be > 0
>
> -# RUN: not ld.lld %t --thinlto-jobs=0 2>&1 | FileCheck --check-prefix=NOTHREADSTHIN %s
> -# RUN: not ld.lld %t --plugin-opt=jobs=0 2>&1 | FileCheck --check-prefix=NOTHREADSTHIN %s
> -# NOTHREADSTHIN: --thinlto-jobs: number of threads must be > 0
> +# RUN: ld.lld %t --thinlto-jobs=0 -verbose 2>&1 | FileCheck --check-prefix=THREADSTHIN %s
> +# RUN: ld.lld %t --thinlto-jobs=1 -verbose 2>&1 | FileCheck --check-prefix=THREADSTHIN %s
> +# RUN: ld.lld %t --thinlto-jobs=2 -verbose 2>&1 | FileCheck --check-prefix=THREADSTHIN %s
> +# RUN: ld.lld %t --thinlto-jobs=all -verbose 2>&1 | FileCheck --check-prefix=THREADSTHIN %s
> +# RUN: ld.lld %t --thinlto-jobs=1000 -verbose 2>&1 | FileCheck --check-prefix=THREADSTHIN %s
> +# THREADSTHIN: basic.s.tmp
> +# RUN: not ld.lld %t --thinlto-jobs=foo -verbose 2>&1 | FileCheck --check-prefix=BADTHREADSTHIN %s
> +# BADTHREADSTHIN: error: --thinlto-jobs: invalid job count: foo
> +
> +# RUN: ld.lld %t --plugin-opt=jobs=0 -verbose 2>&1 | FileCheck --check-prefix=THREADSTHIN %s
> +# RUN: ld.lld %t --plugin-opt=jobs=1 -verbose 2>&1 | FileCheck --check-prefix=THREADSTHIN %s
> +# RUN: ld.lld %t --plugin-opt=jobs=2 -verbose 2>&1 | FileCheck --check-prefix=THREADSTHIN %s
> +# RUN: ld.lld %t --plugin-opt=jobs=all -verbose 2>&1 | FileCheck --check-prefix=THREADSTHIN %s
> +# RUN: ld.lld %t --plugin-opt=jobs=1000 -verbose 2>&1 | FileCheck --check-prefix=THREADSTHIN %s
> +# RUN: not ld.lld %t --plugin-opt=jobs=foo -verbose 2>&1 | FileCheck --check-prefix=BADTHREADSTHIN %s
>
> # RUN: not ld.lld %t -z ifunc-noplt -z text 2>&1 | FileCheck --check-prefix=NOIFUNCPLTNOTEXTREL %s
> # NOIFUNCPLTNOTEXTREL: -z text and -z ifunc-noplt may not be used together
>
> diff --git a/lld/test/ELF/lto/thinlto.ll b/lld/test/ELF/lto/thinlto.ll
> index 2a7ffb90f6ff..ce37433f0bf4 100644
> --- a/lld/test/ELF/lto/thinlto.ll
> +++ b/lld/test/ELF/lto/thinlto.ll
> @@ -16,8 +16,25 @@
> ; RUN: llvm-nm %t31.lto.o | FileCheck %s --check-prefix=NM1
> ; RUN: llvm-nm %t32.lto.o | FileCheck %s --check-prefix=NM2
>
> -; Then check without --thinlto-jobs (which currently default to hardware_concurrency)
> -; RUN: ld.lld -shared %t1.o %t2.o -o %t3
> +; Test with all threads, on all cores, on all CPU sockets
> +; RUN: rm -f %t31.lto.o %t32.lto.o
> +; RUN: ld.lld -save-temps --thinlto-jobs=all -shared %t1.o %t2.o -o %t3
> +; RUN: llvm-nm %t31.lto.o | FileCheck %s --check-prefix=NM1
> +; RUN: llvm-nm %t32.lto.o | FileCheck %s --check-prefix=NM2
> +
> +; Test with many more threads than the system has
> +; RUN: rm -f %t31.lto.o %t32.lto.o
> +; RUN: ld.lld -save-temps --thinlto-jobs=1000 -shared %t1.o %t2.o -o %t3
> +; RUN: llvm-nm %t31.lto.o | FileCheck %s --check-prefix=NM1
> +; RUN: llvm-nm %t32.lto.o | FileCheck %s --check-prefix=NM2
> +
> +; Test with a bad value
> +; RUN: rm -f %t31.lto.o %t32.lto.o
> +; RUN: not ld.lld -save-temps --thinlto-jobs=foo -shared %t1.o %t2.o -o %t3 2>&1 | FileCheck %s --check-prefix=BAD-JOBS
> +; BAD-JOBS: error: --thinlto-jobs: invalid job count: foo
> +
> +; Then check without --thinlto-jobs (which currently defaults to heavyweight_hardware_concurrency, meanning one thread per hardware core -- not SMT)
> +; RUN: ld.lld -shared -save-temps %t1.o %t2.o -o %t3
> ; RUN: llvm-nm %t31.lto.o | FileCheck %s --check-prefix=NM1
> ; RUN: llvm-nm %t32.lto.o | FileCheck %s --check-prefix=NM2
>
>
> diff --git a/lld/test/wasm/lto/thinlto.ll b/lld/test/wasm/lto/thinlto.ll
> index 062da1a33b89..460452905597 100644
> --- a/lld/test/wasm/lto/thinlto.ll
> +++ b/lld/test/wasm/lto/thinlto.ll
> @@ -14,8 +14,26 @@
> ; RUN: llvm-nm %t31.lto.o | FileCheck %s --check-prefix=NM1
> ; RUN: llvm-nm %t32.lto.o | FileCheck %s --check-prefix=NM2
>
> -; Check without --thinlto-jobs (which currently default to hardware_concurrency)
> -; RUN: wasm-ld -r %t1.o %t2.o -o %t3
> +; Test with all threads, on all cores, on all CPU sockets
> +; RUN: rm -f %t31.lto.o %t32.lto.o
> +; RUN: wasm-ld -r -save-temps --thinlto-jobs=all %t1.o %t2.o -o %t3
> +; RUN: llvm-nm %t31.lto.o | FileCheck %s --check-prefix=NM1
> +; RUN: llvm-nm %t32.lto.o | FileCheck %s --check-prefix=NM2
> +
> +; Test with many more threads than the system has
> +; RUN: rm -f %t31.lto.o %t32.lto.o
> +; RUN: wasm-ld -r -save-temps --thinlto-jobs=1000 %t1.o %t2.o -o %t3
> +; RUN: llvm-nm %t31.lto.o | FileCheck %s --check-prefix=NM1
> +; RUN: llvm-nm %t32.lto.o | FileCheck %s --check-prefix=NM2
> +
> +; Test with a bad value
> +; RUN: rm -f %t31.lto.o %t32.lto.o
> +; RUN: not wasm-ld -r -save-temps --thinlto-jobs=foo %t1.o %t2.o -o %t3 2>&1 | FileCheck %s --check-prefix=BAD-JOBS
> +; BAD-JOBS: error: --thinlto-jobs: invalid job count: foo
> +
> +; Check without --thinlto-jobs (which currently defaults to heavyweight_hardware_concurrency, meanning one thread per hardware core -- not SMT)
> +; RUN: rm -f %t31.lto.o %t32.lto.o
> +; RUN: wasm-ld -r -save-temps %t1.o %t2.o -o %t3
> ; RUN: llvm-nm %t31.lto.o | FileCheck %s --check-prefix=NM1
> ; RUN: llvm-nm %t32.lto.o | FileCheck %s --check-prefix=NM2
>
>
> diff --git a/lld/wasm/Config.h b/lld/wasm/Config.h
> index 3b3f2daf576c..b396bda93d58 100644
> --- a/lld/wasm/Config.h
> +++ b/lld/wasm/Config.h
> @@ -53,7 +53,7 @@ struct Configuration {
> unsigned ltoPartitions;
> unsigned ltoo;
> unsigned optimize;
> - unsigned thinLTOJobs;
> + llvm::StringRef thinLTOJobs;
>
> llvm::StringRef entry;
> llvm::StringRef outputFile;
>
> diff --git a/lld/wasm/Driver.cpp b/lld/wasm/Driver.cpp
> index 73b330ae1470..b38e980004ad 100644
> --- a/lld/wasm/Driver.cpp
> +++ b/lld/wasm/Driver.cpp
> @@ -362,7 +362,7 @@ static void readConfigs(opt::InputArgList &args) {
> config->thinLTOCachePolicy = CHECK(
> parseCachePruningPolicy(args.getLastArgValue(OPT_thinlto_cache_policy)),
> "--thinlto-cache-policy: invalid cache policy");
> - config->thinLTOJobs = args::getInteger(args, OPT_thinlto_jobs, -1u);
> + config->thinLTOJobs = args.getLastArgValue(OPT_thinlto_jobs);
> errorHandler().verbose = args.hasArg(OPT_verbose);
> LLVM_DEBUG(errorHandler().verbose = true);
> threadsEnabled = args.hasFlag(OPT_threads, OPT_no_threads, true);
> @@ -415,8 +415,8 @@ static void checkOptions(opt::InputArgList &args) {
> error("invalid optimization level for LTO: " + Twine(config->ltoo));
> if (config->ltoPartitions == 0)
> error("--lto-partitions: number of threads must be > 0");
> - if (config->thinLTOJobs == 0)
> - error("--thinlto-jobs: number of threads must be > 0");
> + if (!get_threadpool_strategy(config->thinLTOJobs))
> + error("--thinlto-jobs: invalid job count: " + config->thinLTOJobs);
>
> if (config->pie && config->shared)
> error("-shared and -pie may not be used together");
>
> diff --git a/lld/wasm/LTO.cpp b/lld/wasm/LTO.cpp
> index 0b7d8cb12d0e..28b62022f29f 100644
> --- a/lld/wasm/LTO.cpp
> +++ b/lld/wasm/LTO.cpp
> @@ -63,10 +63,8 @@ static std::unique_ptr<lto::LTO> createLTO() {
> if (config->saveTemps)
> checkError(c.addSaveTemps(config->outputFile.str() + ".",
> /*UseInputModulePath*/ true));
> -
> - lto::ThinBackend backend;
> - if (config->thinLTOJobs != -1U)
> - backend = lto::createInProcessThinBackend(config->thinLTOJobs);
> + lto::ThinBackend backend = lto::createInProcessThinBackend(
> + llvm::heavyweight_hardware_concurrency(config->thinLTOJobs));
> return std::make_unique<lto::LTO>(std::move(c), backend,
> config->ltoPartitions);
> }
>
> diff --git a/llvm/include/llvm/LTO/LTO.h b/llvm/include/llvm/LTO/LTO.h
> index df2853345682..e93439819415 100644
> --- a/llvm/include/llvm/LTO/LTO.h
> +++ b/llvm/include/llvm/LTO/LTO.h
> @@ -228,7 +228,7 @@ using ThinBackend = std::function<std::unique_ptr<ThinBackendProc>(
>
> /// This ThinBackend runs the individual backend jobs in-process.
> /// The default value means to use one job per hardware core (not hyper-thread).
> -ThinBackend createInProcessThinBackend(unsigned ParallelismLevel = 0);
> +ThinBackend createInProcessThinBackend(ThreadPoolStrategy Parallelism);
>
> /// This ThinBackend writes individual module indexes to files, instead of
> /// running the individual backend jobs. This backend is for distributed builds
>
> diff --git a/llvm/include/llvm/Support/Threading.h b/llvm/include/llvm/Support/Threading.h
> index 24a0789e0964..f133c790ad96 100644
> --- a/llvm/include/llvm/Support/Threading.h
> +++ b/llvm/include/llvm/Support/Threading.h
> @@ -166,8 +166,20 @@ void llvm_execute_on_thread_async(
> /// sockets. \p ThreadPoolNum represents a number bounded by [0,
> /// compute_thread_count()).
> void apply_thread_strategy(unsigned ThreadPoolNum) const;
> +
> + /// Finds the CPU socket where a thread should go. Returns 'None' if the
> + /// thread shall remain on the actual CPU socket.
> + Optional<unsigned> compute_cpu_socket(unsigned ThreadPoolNum) const;
> };
>
> + /// Build a strategy from a number of threads as a string provided in \p Num.
> + /// When Num is above the max number of threads specified by the \p Default
> + /// strategy, we attempt to equally allocate the threads on all CPU sockets.
> + /// "0" or an empty string will return the \p Default strategy.
> + /// "all" for using all hardware threads.
> + Optional<ThreadPoolStrategy>
> + get_threadpool_strategy(StringRef Num, ThreadPoolStrategy Default = {});
> +
> /// Returns a thread strategy for tasks requiring significant memory or other
> /// resources. To be used for workloads where hardware_concurrency() proves to
> /// be less efficient. Avoid this strategy if doing lots of I/O. Currently
> @@ -182,6 +194,18 @@ void llvm_execute_on_thread_async(
> return S;
> }
>
> + /// Like heavyweight_hardware_concurrency() above, but builds a strategy
> + /// based on the rules described for get_threadpool_strategy().
> + /// If \p Num is invalid, returns a default strategy where one thread per
> + /// hardware core is used.
> + inline ThreadPoolStrategy heavyweight_hardware_concurrency(StringRef Num) {
> + Optional<ThreadPoolStrategy> S =
> + get_threadpool_strategy(Num, heavyweight_hardware_concurrency());
> + if (S)
> + return *S;
> + return heavyweight_hardware_concurrency();
> + }
> +
> /// Returns a default thread strategy where all available hardware ressources
> /// are to be used, except for those initially excluded by an affinity mask.
> /// This function takes affinity into consideration. Returns 1 when LLVM is
>
> diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp
> index f8affcb20cef..f652bd628770 100644
> --- a/llvm/lib/LTO/LTO.cpp
> +++ b/llvm/lib/LTO/LTO.cpp
> @@ -477,7 +477,8 @@ LTO::RegularLTOState::RegularLTOState(unsigned ParallelCodeGenParallelismLevel,
> LTO::ThinLTOState::ThinLTOState(ThinBackend Backend)
> : Backend(Backend), CombinedIndex(/*HaveGVs*/ false) {
> if (!Backend)
> - this->Backend = createInProcessThinBackend();
> + this->Backend =
> + createInProcessThinBackend(llvm::heavyweight_hardware_concurrency());
> }
>
> LTO::LTO(Config Conf, ThinBackend Backend,
> @@ -1090,13 +1091,12 @@ class InProcessThinBackend : public ThinBackendProc {
> public:
> InProcessThinBackend(
> const Config &Conf, ModuleSummaryIndex &CombinedIndex,
> - unsigned ThinLTOParallelismLevel,
> + ThreadPoolStrategy ThinLTOParallelism,
> const StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries,
> AddStreamFn AddStream, NativeObjectCache Cache)
> : ThinBackendProc(Conf, CombinedIndex, ModuleToDefinedGVSummaries),
> - BackendThreadPool(
> - heavyweight_hardware_concurrency(ThinLTOParallelismLevel)),
> - AddStream(std::move(AddStream)), Cache(std::move(Cache)) {
> + BackendThreadPool(ThinLTOParallelism), AddStream(std::move(AddStream)),
> + Cache(std::move(Cache)) {
> for (auto &Name : CombinedIndex.cfiFunctionDefs())
> CfiFunctionDefs.insert(
> GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(Name)));
> @@ -1192,13 +1192,13 @@ class InProcessThinBackend : public ThinBackendProc {
> };
> } // end anonymous namespace
>
> -ThinBackend lto::createInProcessThinBackend(unsigned ParallelismLevel) {
> +ThinBackend lto::createInProcessThinBackend(ThreadPoolStrategy Parallelism) {
> return [=](const Config &Conf, ModuleSummaryIndex &CombinedIndex,
> const StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries,
> AddStreamFn AddStream, NativeObjectCache Cache) {
> return std::make_unique<InProcessThinBackend>(
> - Conf, CombinedIndex, ParallelismLevel, ModuleToDefinedGVSummaries,
> - AddStream, Cache);
> + Conf, CombinedIndex, Parallelism, ModuleToDefinedGVSummaries, AddStream,
> + Cache);
> };
> }
>
>
> diff --git a/llvm/lib/Support/Threading.cpp b/llvm/lib/Support/Threading.cpp
> index de5adaddd9d3..39de05892981 100644
> --- a/llvm/lib/Support/Threading.cpp
> +++ b/llvm/lib/Support/Threading.cpp
> @@ -84,16 +84,34 @@ void llvm::llvm_execute_on_thread_async(
> int computeHostNumHardwareThreads();
>
> unsigned llvm::ThreadPoolStrategy::compute_thread_count() const {
> + if (ThreadsRequested > 0)
> + return ThreadsRequested;
> +
> int MaxThreadCount = UseHyperThreads ? computeHostNumHardwareThreads()
> : sys::getHostNumPhysicalCores();
> if (MaxThreadCount <= 0)
> MaxThreadCount = 1;
> + return MaxThreadCount;
> +}
>
> - // No need to create more threads than there are hardware threads, it would
> - // uselessly induce more context-switching and cache eviction.
> - if (!ThreadsRequested || ThreadsRequested > (unsigned)MaxThreadCount)
> - return MaxThreadCount;
> - return ThreadsRequested;
> +Optional<ThreadPoolStrategy>
> +llvm::get_threadpool_strategy(StringRef Num, ThreadPoolStrategy Default) {
> + if (Num == "all")
> + return llvm::hardware_concurrency();
> + if (Num.empty())
> + return Default;
> + unsigned V;
> + if (Num.getAsInteger(10, V))
> + return None; // malformed 'Num' value
> + if (V == 0)
> + return Default;
> +
> + // Do not take the Default into account. This effectively disables
> + // heavyweight_hardware_concurrency() if the user asks for any number of
> + // threads on the cmd-line.
> + ThreadPoolStrategy S = llvm::hardware_concurrency();
> + S.ThreadsRequested = V;
> + return S;
> }
>
> namespace {
>
> diff --git a/llvm/lib/Support/Unix/Threading.inc b/llvm/lib/Support/Unix/Threading.inc
> index 8cacaa83e961..307a24469144 100644
> --- a/llvm/lib/Support/Unix/Threading.inc
> +++ b/llvm/lib/Support/Unix/Threading.inc
> @@ -273,7 +273,7 @@ SetThreadPriorityResult llvm::set_thread_priority(ThreadPriority Priority) {
> int computeHostNumHardwareThreads() {
> #if defined(HAVE_SCHED_GETAFFINITY) && defined(HAVE_CPU_COUNT)
> cpu_set_t Set;
> - if (sched_getaffinity(0, sizeof(Set), &Set))
> + if (sched_getaffinity(0, sizeof(Set), &Set) == 0)
> return CPU_COUNT(&Set);
> #endif
> // Guard against std::thread::hardware_concurrency() returning 0.
>
> diff --git a/llvm/lib/Support/Windows/Threading.inc b/llvm/lib/Support/Windows/Threading.inc
> index 50c94068b395..296e87b77695 100644
> --- a/llvm/lib/Support/Windows/Threading.inc
> +++ b/llvm/lib/Support/Windows/Threading.inc
> @@ -131,6 +131,10 @@ struct ProcessorGroup {
> unsigned UsableThreads;
> unsigned ThreadsPerCore;
> uint64_t Affinity;
> +
> + unsigned useableCores() const {
> + return std::max(1U, UsableThreads / ThreadsPerCore);
> + }
> };
>
> template <typename F>
> @@ -232,33 +236,41 @@ int computeHostNumHardwareThreads() {
> return Threads;
> }
>
> -// Assign the current thread to a more appropriate CPU socket or CPU group
> -void llvm::ThreadPoolStrategy::apply_thread_strategy(
> - unsigned ThreadPoolNum) const {
> +// Finds the proper CPU socket where a thread number should go. Returns 'None'
> +// if the thread shall remain on the actual CPU socket.
> +Optional<unsigned>
> +llvm::ThreadPoolStrategy::compute_cpu_socket(unsigned ThreadPoolNum) const {
> ArrayRef<ProcessorGroup> Groups = getProcessorGroups();
> + // Only one CPU socket in the system or process affinity was set, no need to
> + // move the thread(s) to another CPU socket.
> + if (Groups.size() <= 1)
> + return None;
> +
> + // We ask for less threads than there are hardware threads per CPU socket, no
> + // need to dispatch threads to other CPU sockets.
> + unsigned MaxThreadsPerSocket =
> + UseHyperThreads ? Groups[0].UsableThreads : Groups[0].useableCores();
> + if (compute_thread_count() <= MaxThreadsPerSocket)
> + return None;
>
> assert(ThreadPoolNum < compute_thread_count() &&
> "The thread index is not within thread strategy's range!");
>
> - // In this mode, the ThreadNumber represents the core number, not the
> - // hyper-thread number. Assumes all NUMA groups have the same amount of
> - // hyper-threads.
> - if (!UseHyperThreads)
> - ThreadPoolNum *= Groups[0].ThreadsPerCore;
> -
> - unsigned ThreadRangeStart = 0;
> - for (unsigned I = 0; I < Groups.size(); ++I) {
> - const ProcessorGroup &G = Groups[I];
> - if (ThreadPoolNum >= ThreadRangeStart &&
> - ThreadPoolNum < ThreadRangeStart + G.UsableThreads) {
> -
> - GROUP_AFFINITY Affinity{};
> - Affinity.Group = G.ID;
> - Affinity.Mask = G.Affinity;
> - SetThreadGroupAffinity(GetCurrentThread(), &Affinity, nullptr);
> - }
> - ThreadRangeStart += G.UsableThreads;
> - }
> + // Assumes the same number of hardware threads per CPU socket.
> + return (ThreadPoolNum * Groups.size()) / compute_thread_count();
> +}
> +
> +// Assign the current thread to a more appropriate CPU socket or CPU group
> +void llvm::ThreadPoolStrategy::apply_thread_strategy(
> + unsigned ThreadPoolNum) const {
> + Optional<unsigned> Socket = compute_cpu_socket(ThreadPoolNum);
> + if (!Socket)
> + return;
> + ArrayRef<ProcessorGroup> Groups = getProcessorGroups();
> + GROUP_AFFINITY Affinity{};
> + Affinity.Group = Groups[*Socket].ID;
> + Affinity.Mask = Groups[*Socket].Affinity;
> + SetThreadGroupAffinity(GetCurrentThread(), &Affinity, nullptr);
> }
>
> llvm::BitVector llvm::get_thread_affinity_mask() {
>
> diff --git a/llvm/tools/gold/gold-plugin.cpp b/llvm/tools/gold/gold-plugin.cpp
> index 2db571617181..383f972b8636 100644
> --- a/llvm/tools/gold/gold-plugin.cpp
> +++ b/llvm/tools/gold/gold-plugin.cpp
> @@ -28,6 +28,7 @@
> #include "llvm/Support/MemoryBuffer.h"
> #include "llvm/Support/Path.h"
> #include "llvm/Support/TargetSelect.h"
> +#include "llvm/Support/Threading.h"
> #include "llvm/Support/raw_ostream.h"
> #include <list>
> #include <map>
> @@ -134,11 +135,9 @@ namespace options {
> };
> static OutputType TheOutputType = OT_NORMAL;
> static unsigned OptLevel = 2;
> - // Default parallelism of 0 used to indicate that user did not specify.
> - // Actual parallelism default value depends on implementation.
> // Currently only affects ThinLTO, where the default is the max cores in the
> - // system.
> - static unsigned Parallelism = 0;
> + // system. See llvm::get_threadpool_strategy() for acceptable values.
> + static std::string Parallelism;
> // Default regular LTO codegen parallelism (number of partitions).
> static unsigned ParallelCodeGenParallelismLevel = 1;
> #ifdef NDEBUG
> @@ -272,8 +271,10 @@ namespace options {
> message(LDPL_FATAL, "Optimization level must be between 0 and 3");
> OptLevel = opt[1] - '0';
> } else if (opt.startswith("jobs=")) {
> - if (StringRef(opt_ + 5).getAsInteger(10, Parallelism))
> - message(LDPL_FATAL, "Invalid parallelism level: %s", opt_ + 5);
> + StringRef Num(opt_ + 5);
> + if (!get_threadpool_strategy(Num))
> + message(LDPL_FATAL, "Invalid parallelism level: %s", Num.data());
> + Parallelism = Num;
> } else if (opt.startswith("lto-partitions=")) {
> if (opt.substr(strlen("lto-partitions="))
> .getAsInteger(10, ParallelCodeGenParallelismLevel))
> @@ -877,14 +878,15 @@ static std::unique_ptr<LTO> createLTO(IndexWriteCallback OnIndexWrite,
> Conf.PTO.LoopVectorization = options::OptLevel > 1;
> Conf.PTO.SLPVectorization = options::OptLevel > 1;
>
> - if (options::Parallelism)
> - Backend = createInProcessThinBackend(options::Parallelism);
> if (options::thinlto_index_only) {
> std::string OldPrefix, NewPrefix;
> getThinLTOOldAndNewPrefix(OldPrefix, NewPrefix);
> Backend = createWriteIndexesThinBackend(OldPrefix, NewPrefix,
> options::thinlto_emit_imports_files,
> LinkedObjectsFile, OnIndexWrite);
> + } else {
> + Backend = createInProcessThinBackend(
> + llvm::heavyweight_hardware_concurrency(options::Parallelism));
> }
>
> Conf.OverrideTriple = options::triple;
>
> diff --git a/llvm/tools/llvm-lto2/llvm-lto2.cpp b/llvm/tools/llvm-lto2/llvm-lto2.cpp
> index dda596be0ce6..6d78082f980e 100644
> --- a/llvm/tools/llvm-lto2/llvm-lto2.cpp
> +++ b/llvm/tools/llvm-lto2/llvm-lto2.cpp
> @@ -68,9 +68,10 @@ static cl::opt<bool>
> "distributed backend case"));
>
> // Default to using all available threads in the system, but using only one
> -// thread per core, as indicated by the usage of
> -// heavyweight_hardware_concurrency() in the InProcessThinBackend constructor.
> -static cl::opt<int> Threads("thinlto-threads", cl::init(0));
> +// thread per core (no SMT).
> +// Use -thinlto-threads=all to use hardware_concurrency() instead, which means
> +// to use all hardware threads or cores in the system.
> +static cl::opt<std::string> Threads("thinlto-threads");
>
> static cl::list<std::string> SymbolResolutions(
> "r",
> @@ -286,7 +287,8 @@ static int run(int argc, char **argv) {
> /* LinkedObjectsFile */ nullptr,
> /* OnWrite */ {});
> else
> - Backend = createInProcessThinBackend(Threads);
> + Backend = createInProcessThinBackend(
> + llvm::heavyweight_hardware_concurrency(Threads));
> LTO Lto(std::move(Conf), std::move(Backend));
>
> bool HasErrors = false;
>
>
>
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