[Openmp-commits] [openmp] [Libomptarget] Only initialize a plugin if a device image needs it (PR #76174)
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openmp-commits at lists.llvm.org
Thu Dec 21 11:30:59 PST 2023
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-backend-amdgpu
Author: Joseph Huber (jhuber6)
<details>
<summary>Changes</summary>
Summary:
This patch changes the image registration logic. Currently, we
initialize every single plugin even if no images will end up using it.
This patch adds a new pair of runtime calls. The first one checks if the
plugin has been initialized or is active. The second does a light-weight
check on the ELF machine to prevent it from needing to initialize a
plugin with a trivially incompatible image.
My machine has CUDA and AMDGPU installed. This patch saves roughly 20ms
when compiling only for the AMDGPU device with a trivial program. and
roughly 30ms when compiling only for the NVPTX device with a trivial
program.
---
Full diff: https://github.com/llvm/llvm-project/pull/76174.diff
12 Files Affected:
- (modified) openmp/libomptarget/include/PluginManager.h (+4)
- (modified) openmp/libomptarget/include/Shared/PluginAPI.h (+14-1)
- (modified) openmp/libomptarget/include/Shared/PluginAPI.inc (+2)
- (modified) openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp (+3-1)
- (modified) openmp/libomptarget/plugins-nextgen/common/include/JIT.h (+1-1)
- (modified) openmp/libomptarget/plugins-nextgen/common/include/PluginInterface.h (+5-2)
- (modified) openmp/libomptarget/plugins-nextgen/common/src/JIT.cpp (+9-15)
- (modified) openmp/libomptarget/plugins-nextgen/common/src/PluginInterface.cpp (+56-22)
- (modified) openmp/libomptarget/plugins-nextgen/common/src/Utils/ELF.cpp (+1-2)
- (modified) openmp/libomptarget/plugins-nextgen/cuda/src/rtl.cpp (+3-1)
- (modified) openmp/libomptarget/plugins-nextgen/generic-elf-64bit/src/rtl.cpp (+3-1)
- (modified) openmp/libomptarget/src/PluginManager.cpp (+40-17)
``````````diff
diff --git a/openmp/libomptarget/include/PluginManager.h b/openmp/libomptarget/include/PluginManager.h
index a0499c37504c0d..7128e14bdf6fc0 100644
--- a/openmp/libomptarget/include/PluginManager.h
+++ b/openmp/libomptarget/include/PluginManager.h
@@ -49,6 +49,10 @@ struct PluginAdaptorTy {
/// that fail to initialize are ignored.
void initDevices(PluginManager &PM);
+ /// Initialize as many devices as possible for this plugin adaptor. Devices
+ /// that fail to initialize are ignored.
+ llvm::Error initPlugin();
+
bool isUsed() const { return DeviceOffset >= 0; }
/// Return the number of devices visible to the underlying plugin.
diff --git a/openmp/libomptarget/include/Shared/PluginAPI.h b/openmp/libomptarget/include/Shared/PluginAPI.h
index c6aacf4ce2124b..2a2eebb06bfea4 100644
--- a/openmp/libomptarget/include/Shared/PluginAPI.h
+++ b/openmp/libomptarget/include/Shared/PluginAPI.h
@@ -20,14 +20,27 @@
#include "Shared/APITypes.h"
extern "C" {
-
// First method called on the plugin
int32_t __tgt_rtl_init_plugin();
+// Returns non-zero if the plugin has been initialized.
+int32_t __tgt_rtl_is_plugin_active();
+
// Return the number of available devices of the type supported by the
// target RTL.
int32_t __tgt_rtl_number_of_devices(void);
+// Returns a non-zero integer if the given Image is capable of being run by the
+// plugin. This is intended to be called without initializing the plugin.
+int32_t __tgt_rtl_is_binary_compatible(__tgt_device_image *Image);
+
+// Return an integer different from zero if the provided device image can be
+// supported by the runtime. The functionality is similar to comparing the
+// result of __tgt__rtl__load__binary to NULL. However, this is meant to be a
+// lightweight query to determine if the RTL is suitable for an image without
+// having to load the library, which can be expensive.
+int32_t __tgt_rtl_is_valid_binary(__tgt_device_image *Image);
+
// Return an integer different from zero if the provided device image can be
// supported by the runtime. The functionality is similar to comparing the
// result of __tgt__rtl__load__binary to NULL. However, this is meant to be a
diff --git a/openmp/libomptarget/include/Shared/PluginAPI.inc b/openmp/libomptarget/include/Shared/PluginAPI.inc
index 25ebe7d437f9d1..7b24c459eda3b1 100644
--- a/openmp/libomptarget/include/Shared/PluginAPI.inc
+++ b/openmp/libomptarget/include/Shared/PluginAPI.inc
@@ -14,6 +14,8 @@
// No include guards!
PLUGIN_API_HANDLE(init_plugin, true);
+PLUGIN_API_HANDLE(is_plugin_active, true);
+PLUGIN_API_HANDLE(is_binary_compatible, true);
PLUGIN_API_HANDLE(is_valid_binary, true);
PLUGIN_API_HANDLE(is_data_exchangable, false);
PLUGIN_API_HANDLE(number_of_devices, true);
diff --git a/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp b/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp
index fe435a3f558557..6d9e2cb30da7fc 100644
--- a/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp
+++ b/openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp
@@ -56,6 +56,8 @@
#include "hsa/hsa_ext_amd.h"
#endif
+extern const uint16_t llvm::omp::target::plugin::ELFMachine = ELF::EM_AMDGPU;
+
namespace llvm {
namespace omp {
namespace target {
@@ -3013,7 +3015,7 @@ struct AMDGPUPluginTy final : public GenericPluginTy {
Triple::ArchType getTripleArch() const override { return Triple::amdgcn; }
/// Get the ELF code for recognizing the compatible image binary.
- uint16_t getMagicElfBits() const override { return ELF::EM_AMDGPU; }
+ uint16_t getMagicElfBits() const override { return ELFMachine; }
/// Check whether the image is compatible with an AMDGPU device.
Expected<bool> isELFCompatible(StringRef Image) const override {
diff --git a/openmp/libomptarget/plugins-nextgen/common/include/JIT.h b/openmp/libomptarget/plugins-nextgen/common/include/JIT.h
index 3ec4424f856a00..b22197b8920838 100644
--- a/openmp/libomptarget/plugins-nextgen/common/include/JIT.h
+++ b/openmp/libomptarget/plugins-nextgen/common/include/JIT.h
@@ -57,7 +57,7 @@ struct JITEngine {
/// Return true if \p Image is a bitcode image that can be JITed for the given
/// architecture.
- bool checkBitcodeImage(const __tgt_device_image &Image);
+ Expected<bool> checkBitcodeImage(StringRef Buffer) const;
private:
/// Compile the bitcode image \p Image and generate the binary image that can
diff --git a/openmp/libomptarget/plugins-nextgen/common/include/PluginInterface.h b/openmp/libomptarget/plugins-nextgen/common/include/PluginInterface.h
index cf02783d8b3388..012c4ccbd87db4 100644
--- a/openmp/libomptarget/plugins-nextgen/common/include/PluginInterface.h
+++ b/openmp/libomptarget/plugins-nextgen/common/include/PluginInterface.h
@@ -48,9 +48,12 @@
namespace llvm {
namespace omp {
namespace target {
-
namespace plugin {
+/// The plugin's native ELF architecture. This should be defined individually
+/// by each plugin, and ELF:EM_NONE if the ELF target is not applicable.
+extern const uint16_t ELFMachine;
+
struct GenericPluginTy;
struct GenericKernelTy;
struct GenericDeviceTy;
@@ -1067,7 +1070,7 @@ struct GenericPluginTy {
/// Top level interface to verify if a given ELF image can be executed on a
/// given target. Returns true if the \p Image is compatible with the plugin.
- Expected<bool> checkELFImage(__tgt_device_image &Image) const;
+ Expected<bool> checkELFImage(StringRef Image) const;
/// Indicate if an image is compatible with the plugin devices. Notice that
/// this function may be called before actually initializing the devices. So
diff --git a/openmp/libomptarget/plugins-nextgen/common/src/JIT.cpp b/openmp/libomptarget/plugins-nextgen/common/src/JIT.cpp
index 08080c9d6091bb..7275be4edfca5b 100644
--- a/openmp/libomptarget/plugins-nextgen/common/src/JIT.cpp
+++ b/openmp/libomptarget/plugins-nextgen/common/src/JIT.cpp
@@ -330,24 +330,18 @@ JITEngine::process(const __tgt_device_image &Image,
return &Image;
}
-bool JITEngine::checkBitcodeImage(const __tgt_device_image &Image) {
+Expected<bool> JITEngine::checkBitcodeImage(StringRef Buffer) const {
TimeTraceScope TimeScope("Check bitcode image");
- if (!isImageBitcode(Image))
- return false;
-
- StringRef Data(reinterpret_cast<const char *>(Image.ImageStart),
- target::getPtrDiff(Image.ImageEnd, Image.ImageStart));
- auto MB = MemoryBuffer::getMemBuffer(Data, /*BufferName=*/"",
- /*RequiresNullTerminator=*/false);
- if (!MB)
- return false;
+ assert(identify_magic(Buffer) == file_magic::bitcode &&
+ "Input is not bitcode");
LLVMContext Context;
- SMDiagnostic Diagnostic;
- std::unique_ptr<Module> M =
- llvm::getLazyIRModule(std::move(MB), Diagnostic, Context,
- /*ShouldLazyLoadMetadata=*/true);
+ auto ModuleOrErr = getLazyBitcodeModule(MemoryBufferRef(Buffer, ""), Context,
+ /*ShouldLazyLoadMetadata=*/true);
+ if (!ModuleOrErr)
+ return ModuleOrErr.takeError();
+ Module &M = **ModuleOrErr;
- return M && Triple(M->getTargetTriple()).getArch() == TT.getArch();
+ return Triple(M.getTargetTriple()).getArch() == TT.getArch();
}
diff --git a/openmp/libomptarget/plugins-nextgen/common/src/PluginInterface.cpp b/openmp/libomptarget/plugins-nextgen/common/src/PluginInterface.cpp
index 178c60a77ab51f..9b63e6bd4b31b6 100644
--- a/openmp/libomptarget/plugins-nextgen/common/src/PluginInterface.cpp
+++ b/openmp/libomptarget/plugins-nextgen/common/src/PluginInterface.cpp
@@ -1632,16 +1632,13 @@ Error GenericPluginTy::deinitDevice(int32_t DeviceId) {
return Plugin::success();
}
-Expected<bool> GenericPluginTy::checkELFImage(__tgt_device_image &Image) const {
- StringRef Buffer(reinterpret_cast<const char *>(Image.ImageStart),
- target::getPtrDiff(Image.ImageEnd, Image.ImageStart));
-
+Expected<bool> GenericPluginTy::checkELFImage(StringRef Image) const {
// First check if this image is a regular ELF file.
- if (!utils::elf::isELF(Buffer))
+ if (!utils::elf::isELF(Image))
return false;
// Check if this image is an ELF with a matching machine value.
- auto MachineOrErr = utils::elf::checkMachine(Buffer, getMagicElfBits());
+ auto MachineOrErr = utils::elf::checkMachine(Image, getMagicElfBits());
if (!MachineOrErr)
return MachineOrErr.takeError();
@@ -1649,7 +1646,7 @@ Expected<bool> GenericPluginTy::checkELFImage(__tgt_device_image &Image) const {
return false;
// Perform plugin-dependent checks for the specific architecture if needed.
- return isELFCompatible(Buffer);
+ return isELFCompatible(Image);
}
const bool llvm::omp::target::plugin::libomptargetSupportsRPC() {
@@ -1678,27 +1675,64 @@ int32_t __tgt_rtl_init_plugin() {
return OFFLOAD_SUCCESS;
}
-int32_t __tgt_rtl_is_valid_binary(__tgt_device_image *TgtImage) {
- // TODO: We should be able to perform a trivial ELF machine check without
- // initializing the plugin first to save time if the plugin is not needed.
+int32_t __tgt_rtl_is_plugin_active() { return Plugin::isActive(); }
+
+int32_t __tgt_rtl_is_binary_compatible(__tgt_device_image *Image) {
+ assert(!Plugin::isActive() && "Should not be called after initialization");
+
+ StringRef Buffer(reinterpret_cast<const char *>(Image->ImageStart),
+ target::getPtrDiff(Image->ImageEnd, Image->ImageStart));
+
+ switch (identify_magic(Buffer)) {
+ case file_magic::elf:
+ case file_magic::elf_executable:
+ case file_magic::elf_shared_object: {
+ // Check if this image is an ELF with a matching machine value.
+ auto MachineOrErr = utils::elf::checkMachine(Buffer, ELFMachine);
+ if (Error Err = MachineOrErr.takeError()) {
+ consumeError(std::move(Err));
+ return false;
+ }
+ return *MachineOrErr;
+ }
+ default:
+ // Assume this image is compatible and check if it's a valid binary later.
+ return true;
+ }
+}
+
+int32_t __tgt_rtl_is_valid_binary(__tgt_device_image *Image) {
if (!Plugin::isActive())
return false;
- // Check if this is a valid ELF with a matching machine and processor.
- auto MatchOrErr = Plugin::get().checkELFImage(*TgtImage);
- if (Error Err = MatchOrErr.takeError()) {
+ StringRef Buffer(reinterpret_cast<const char *>(Image->ImageStart),
+ target::getPtrDiff(Image->ImageEnd, Image->ImageStart));
+
+ auto HandleError = [&](Error Err) -> bool {
[[maybe_unused]] std::string ErrStr = toString(std::move(Err));
- DP("Failure to check validity of image %p: %s", TgtImage, ErrStr.c_str());
+ DP("Failure to check validity of image %p: %s", Image, ErrStr.c_str());
+ return false;
+ };
+ switch (identify_magic(Buffer)) {
+ case file_magic::elf:
+ case file_magic::elf_relocatable:
+ case file_magic::elf_executable:
+ case file_magic::elf_shared_object:
+ case file_magic::elf_core: {
+ auto MatchOrErr = Plugin::get().checkELFImage(Buffer);
+ if (Error Err = MatchOrErr.takeError())
+ return HandleError(std::move(Err));
+ return *MatchOrErr;
+ }
+ case file_magic::bitcode: {
+ auto MatchOrErr = Plugin::get().getJIT().checkBitcodeImage(Buffer);
+ if (Error Err = MatchOrErr.takeError())
+ return HandleError(std::move(Err));
+ return *MatchOrErr;
+ }
+ default:
return false;
- } else if (*MatchOrErr) {
- return true;
}
-
- // Check if this is a valid LLVM-IR file with matching triple.
- if (Plugin::get().getJIT().checkBitcodeImage(*TgtImage))
- return true;
-
- return false;
}
int32_t __tgt_rtl_supports_empty_images() {
diff --git a/openmp/libomptarget/plugins-nextgen/common/src/Utils/ELF.cpp b/openmp/libomptarget/plugins-nextgen/common/src/Utils/ELF.cpp
index bdac6c1db5d23a..c84c3bad5def0a 100644
--- a/openmp/libomptarget/plugins-nextgen/common/src/Utils/ELF.cpp
+++ b/openmp/libomptarget/plugins-nextgen/common/src/Utils/ELF.cpp
@@ -37,8 +37,7 @@ bool utils::elf::isELF(StringRef Buffer) {
}
Expected<bool> utils::elf::checkMachine(StringRef Object, uint16_t EMachine) {
- if (!isELF(Object))
- return createError("Input is not an ELF.");
+ assert(isELF(Object) && "Input is not an ELF!");
Expected<ELF64LEObjectFile> ElfOrErr =
ELF64LEObjectFile::create(MemoryBufferRef(Object, /*Identifier=*/""),
diff --git a/openmp/libomptarget/plugins-nextgen/cuda/src/rtl.cpp b/openmp/libomptarget/plugins-nextgen/cuda/src/rtl.cpp
index b0dff917dd0be0..624340af5c1f93 100644
--- a/openmp/libomptarget/plugins-nextgen/cuda/src/rtl.cpp
+++ b/openmp/libomptarget/plugins-nextgen/cuda/src/rtl.cpp
@@ -29,6 +29,8 @@
#include "llvm/Frontend/OpenMP/OMPGridValues.h"
#include "llvm/Support/Error.h"
+extern const uint16_t llvm::omp::target::plugin::ELFMachine = ELF::EM_CUDA;
+
namespace llvm {
namespace omp {
namespace target {
@@ -1275,7 +1277,7 @@ struct CUDAPluginTy final : public GenericPluginTy {
Error deinitImpl() override { return Plugin::success(); }
/// Get the ELF code for recognizing the compatible image binary.
- uint16_t getMagicElfBits() const override { return ELF::EM_CUDA; }
+ uint16_t getMagicElfBits() const override { return ELFMachine; }
Triple::ArchType getTripleArch() const override {
// TODO: I think we can drop the support for 32-bit NVPTX devices.
diff --git a/openmp/libomptarget/plugins-nextgen/generic-elf-64bit/src/rtl.cpp b/openmp/libomptarget/plugins-nextgen/generic-elf-64bit/src/rtl.cpp
index 88b5236d31f482..499a3e37d44c62 100644
--- a/openmp/libomptarget/plugins-nextgen/generic-elf-64bit/src/rtl.cpp
+++ b/openmp/libomptarget/plugins-nextgen/generic-elf-64bit/src/rtl.cpp
@@ -38,6 +38,8 @@
#define TARGET_ELF_ID ELF::EM_NONE
#endif
+extern const uint16_t llvm::omp::target::plugin::ELFMachine = TARGET_ELF_ID;
+
namespace llvm {
namespace omp {
namespace target {
@@ -389,7 +391,7 @@ struct GenELF64PluginTy final : public GenericPluginTy {
Error deinitImpl() override { return Plugin::success(); }
/// Get the ELF code to recognize the compatible binary images.
- uint16_t getMagicElfBits() const override { return TARGET_ELF_ID; }
+ uint16_t getMagicElfBits() const override { return ELFMachine; }
/// This plugin does not support exchanging data between two devices.
bool isDataExchangable(int32_t SrcDeviceId, int32_t DstDeviceId) override {
diff --git a/openmp/libomptarget/src/PluginManager.cpp b/openmp/libomptarget/src/PluginManager.cpp
index da2e08180eead8..510dc54774ab7f 100644
--- a/openmp/libomptarget/src/PluginManager.cpp
+++ b/openmp/libomptarget/src/PluginManager.cpp
@@ -69,23 +69,6 @@ Error PluginAdaptorTy::init() {
#include "Shared/PluginAPI.inc"
#undef PLUGIN_API_HANDLE
- // Remove plugin on failure to call optional init_plugin
- int32_t Rc = init_plugin();
- if (Rc != OFFLOAD_SUCCESS) {
- return createStringError(inconvertibleErrorCode(),
- "Unable to initialize library '%s': %u!\n",
- Name.c_str(), Rc);
- }
-
- // No devices are supported by this RTL?
- NumberOfPluginDevices = number_of_devices();
- if (!NumberOfPluginDevices) {
- return createStringError(inconvertibleErrorCode(),
- "No devices supported in this RTL\n");
- }
-
- DP("Registered '%s' with %d plugin visible devices!\n", Name.c_str(),
- NumberOfPluginDevices);
return Error::success();
}
@@ -162,6 +145,28 @@ void PluginAdaptorTy::initDevices(PluginManager &PM) {
NumberOfPluginDevices);
}
+Error PluginAdaptorTy::initPlugin() {
+ // Remove plugin on failure to call optional init_plugin
+ int32_t Rc = init_plugin();
+ if (Rc != OFFLOAD_SUCCESS) {
+ return createStringError(inconvertibleErrorCode(),
+ "Unable to initialize library '%s': %u!\n",
+ Name.c_str(), Rc);
+ }
+
+ // No devices are supported by this RTL?
+ NumberOfPluginDevices = number_of_devices();
+ if (!NumberOfPluginDevices) {
+ return createStringError(inconvertibleErrorCode(),
+ "No devices supported in this RTL\n");
+ }
+
+ DP("Registered '%s' with %d plugin visible devices!\n", Name.c_str(),
+ NumberOfPluginDevices);
+
+ return Error::success();
+}
+
void PluginManager::initAllPlugins() {
for (auto &R : PluginAdaptors)
R->initDevices(*this);
@@ -203,6 +208,24 @@ void PluginManager::registerLib(__tgt_bin_desc *Desc) {
for (int32_t i = 0; i < Desc->NumDeviceImages; ++i)
PM->addDeviceImage(*Desc, Desc->DeviceImages[i]);
+ // Initialize any needed plugins using the image metadata if needed.
+ for (auto &R : PM->pluginAdaptors()) {
+ if (R.is_plugin_active())
+ continue;
+
+ // We can skip initializing this image if there are no images for it.
+ for (DeviceImageTy &DI : PM->deviceImages()) {
+ if (R.is_binary_compatible(&DI.getExecutableImage())) {
+ if (Error Err = R.initPlugin()) {
+ [[maybe_unused]] std::string InfoMsg = toString(std::move(Err));
+ DP("Failed to init plugin: %s", InfoMsg.c_str());
+ }
+
+ break;
+ }
+ }
+ }
+
// Register the images with the RTLs that understand them, if any.
for (DeviceImageTy &DI : PM->deviceImages()) {
// Obtain the image and information that was previously extracted.
``````````
</details>
https://github.com/llvm/llvm-project/pull/76174
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