[llvm] 8003f55 - Reland "[llvm-exegesis] Add thread IDs to subprocess memory names (#84451)"
Aiden Grossman via llvm-commits
llvm-commits at lists.llvm.org
Tue Mar 12 16:35:46 PDT 2024
Author: Aiden Grossman
Date: 2024-03-12T16:35:05-07:00
New Revision: 8003f553a01a9a2a7eb09fe07e88f1ba9ee7d3a7
URL: https://github.com/llvm/llvm-project/commit/8003f553a01a9a2a7eb09fe07e88f1ba9ee7d3a7
DIFF: https://github.com/llvm/llvm-project/commit/8003f553a01a9a2a7eb09fe07e88f1ba9ee7d3a7.diff
LOG: Reland "[llvm-exegesis] Add thread IDs to subprocess memory names (#84451)"
This reverts commit aefad27096bba513f06162fac2763089578f3de4.
This relands commit 6bbe8a296ee91754d423c59c35727eaa624f7140.
This patch was casuing build failures on non-Linux platforms due to the
default implementations for the functions not being updated. This ended
up causing out-of-line definition errors. Fixed for the relanding.
Added:
Modified:
llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
llvm/tools/llvm-exegesis/lib/SubprocessMemory.cpp
llvm/tools/llvm-exegesis/lib/SubprocessMemory.h
llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp
Removed:
################################################################################
diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
index 5c9848f3c68885..4e97d188d17259 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
@@ -301,6 +301,7 @@ class SubProcessFunctionExecutorImpl
if (AddMemDefError)
return AddMemDefError;
+ long ParentTID = SubprocessMemory::getCurrentTID();
pid_t ParentOrChildPID = fork();
if (ParentOrChildPID == -1) {
@@ -314,7 +315,7 @@ class SubProcessFunctionExecutorImpl
// Unregister handlers, signal handling is now handled through ptrace in
// the host process.
sys::unregisterHandlers();
- prepareAndRunBenchmark(PipeFiles[0], Key);
+ prepareAndRunBenchmark(PipeFiles[0], Key, ParentTID);
// The child process terminates in the above function, so we should never
// get to this point.
llvm_unreachable("Child process didn't exit when expected.");
@@ -415,8 +416,8 @@ class SubProcessFunctionExecutorImpl
setrlimit(RLIMIT_CORE, &rlim);
}
- [[noreturn]] void prepareAndRunBenchmark(int Pipe,
- const BenchmarkKey &Key) const {
+ [[noreturn]] void prepareAndRunBenchmark(int Pipe, const BenchmarkKey &Key,
+ long ParentTID) const {
// Disable core dumps in the child process as otherwise everytime we
// encounter an execution failure like a segmentation fault, we will create
// a core dump. We report the information directly rather than require the
@@ -473,7 +474,7 @@ class SubProcessFunctionExecutorImpl
Expected<int> AuxMemFDOrError =
SubprocessMemory::setupAuxiliaryMemoryInSubprocess(
- Key.MemoryValues, ParentPID, CounterFileDescriptor);
+ Key.MemoryValues, ParentPID, ParentTID, CounterFileDescriptor);
if (!AuxMemFDOrError)
exit(ChildProcessExitCodeE::AuxiliaryMemorySetupFailed);
diff --git a/llvm/tools/llvm-exegesis/lib/SubprocessMemory.cpp b/llvm/tools/llvm-exegesis/lib/SubprocessMemory.cpp
index a49fa077257d00..1fd81bd407becb 100644
--- a/llvm/tools/llvm-exegesis/lib/SubprocessMemory.cpp
+++ b/llvm/tools/llvm-exegesis/lib/SubprocessMemory.cpp
@@ -9,11 +9,13 @@
#include "SubprocessMemory.h"
#include "Error.h"
#include "llvm/Support/Error.h"
+#include "llvm/Support/FormatVariadic.h"
#include <cerrno>
#ifdef __linux__
#include <fcntl.h>
#include <sys/mman.h>
+#include <sys/syscall.h>
#include <unistd.h>
#endif
@@ -22,12 +24,21 @@ namespace exegesis {
#if defined(__linux__) && !defined(__ANDROID__)
+long SubprocessMemory::getCurrentTID() {
+ // We're using the raw syscall here rather than the gettid() function provided
+ // by most libcs for compatibility as gettid() was only added to glibc in
+ // version 2.30.
+ return syscall(SYS_gettid);
+}
+
Error SubprocessMemory::initializeSubprocessMemory(pid_t ProcessID) {
// Add the PID to the shared memory name so that if we're running multiple
// processes at the same time, they won't interfere with each other.
// This comes up particularly often when running the exegesis tests with
- // llvm-lit
- std::string AuxiliaryMemoryName = "/auxmem" + std::to_string(ProcessID);
+ // llvm-lit. Additionally add the TID so that downstream consumers
+ // using multiple threads don't run into conflicts.
+ std::string AuxiliaryMemoryName =
+ formatv("/{0}auxmem{1}", getCurrentTID(), ProcessID);
int AuxiliaryMemoryFD = shm_open(AuxiliaryMemoryName.c_str(),
O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
if (AuxiliaryMemoryFD == -1)
@@ -47,8 +58,8 @@ Error SubprocessMemory::addMemoryDefinition(
pid_t ProcessPID) {
SharedMemoryNames.reserve(MemoryDefinitions.size());
for (auto &[Name, MemVal] : MemoryDefinitions) {
- std::string SharedMemoryName = "/" + std::to_string(ProcessPID) + "memdef" +
- std::to_string(MemVal.Index);
+ std::string SharedMemoryName =
+ formatv("/{0}t{1}memdef{2}", ProcessPID, getCurrentTID(), MemVal.Index);
SharedMemoryNames.push_back(SharedMemoryName);
int SharedMemoryFD =
shm_open(SharedMemoryName.c_str(), O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
@@ -82,8 +93,9 @@ Error SubprocessMemory::addMemoryDefinition(
Expected<int> SubprocessMemory::setupAuxiliaryMemoryInSubprocess(
std::unordered_map<std::string, MemoryValue> MemoryDefinitions,
- pid_t ParentPID, int CounterFileDescriptor) {
- std::string AuxiliaryMemoryName = "/auxmem" + std::to_string(ParentPID);
+ pid_t ParentPID, long ParentTID, int CounterFileDescriptor) {
+ std::string AuxiliaryMemoryName =
+ formatv("/{0}auxmem{1}", ParentTID, ParentPID);
int AuxiliaryMemoryFileDescriptor =
shm_open(AuxiliaryMemoryName.c_str(), O_RDWR, S_IRUSR | S_IWUSR);
if (AuxiliaryMemoryFileDescriptor == -1)
@@ -97,8 +109,8 @@ Expected<int> SubprocessMemory::setupAuxiliaryMemoryInSubprocess(
return make_error<Failure>("Mapping auxiliary memory failed");
AuxiliaryMemoryMapping[0] = CounterFileDescriptor;
for (auto &[Name, MemVal] : MemoryDefinitions) {
- std::string MemoryValueName = "/" + std::to_string(ParentPID) + "memdef" +
- std::to_string(MemVal.Index);
+ std::string MemoryValueName =
+ formatv("/{0}t{1}memdef{2}", ParentPID, ParentTID, MemVal.Index);
AuxiliaryMemoryMapping[AuxiliaryMemoryOffset + MemVal.Index] =
shm_open(MemoryValueName.c_str(), O_RDWR, S_IRUSR | S_IWUSR);
if (AuxiliaryMemoryMapping[AuxiliaryMemoryOffset + MemVal.Index] == -1)
@@ -133,7 +145,7 @@ Error SubprocessMemory::addMemoryDefinition(
Expected<int> SubprocessMemory::setupAuxiliaryMemoryInSubprocess(
std::unordered_map<std::string, MemoryValue> MemoryDefinitions,
- pid_t ParentPID, int CounterFileDescriptor) {
+ pid_t ParentPID, long ParentTID, int CounterFileDescriptor) {
return make_error<Failure>(
"setupAuxiliaryMemoryInSubprocess is only supported on Linux");
}
diff --git a/llvm/tools/llvm-exegesis/lib/SubprocessMemory.h b/llvm/tools/llvm-exegesis/lib/SubprocessMemory.h
index e20b50cdc8118f..572d1085d9cffa 100644
--- a/llvm/tools/llvm-exegesis/lib/SubprocessMemory.h
+++ b/llvm/tools/llvm-exegesis/lib/SubprocessMemory.h
@@ -35,6 +35,9 @@ class SubprocessMemory {
static constexpr const size_t AuxiliaryMemoryOffset = 1;
static constexpr const size_t AuxiliaryMemorySize = 4096;
+ // Gets the thread ID for the calling thread.
+ static long getCurrentTID();
+
Error initializeSubprocessMemory(pid_t ProcessID);
// The following function sets up memory definitions. It creates shared
@@ -54,7 +57,7 @@ class SubprocessMemory {
// section.
static Expected<int> setupAuxiliaryMemoryInSubprocess(
std::unordered_map<std::string, MemoryValue> MemoryDefinitions,
- pid_t ParentPID, int CounterFileDescriptor);
+ pid_t ParentPID, long ParentTID, int CounterFileDescriptor);
~SubprocessMemory();
diff --git a/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp b/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp
index c07ec188a602c4..7c23e7b7e9c5a5 100644
--- a/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp
+++ b/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp
@@ -17,6 +17,7 @@
#include <endian.h>
#include <fcntl.h>
#include <sys/mman.h>
+#include <sys/syscall.h>
#include <unistd.h>
#endif // __linux__
@@ -49,7 +50,9 @@ class SubprocessMemoryTest : public X86TestBase {
std::string getSharedMemoryName(const unsigned TestNumber,
const unsigned DefinitionNumber) {
- return "/" + std::to_string(getSharedMemoryNumber(TestNumber)) + "memdef" +
+ long CurrentTID = syscall(SYS_gettid);
+ return "/" + std::to_string(getSharedMemoryNumber(TestNumber)) + "t" +
+ std::to_string(CurrentTID) + "memdef" +
std::to_string(DefinitionNumber);
}
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