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Use CS PGO for LLVM #111806

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8fb3161
Use CS PGO for LLVM
Kobzol May 20, 2023
71c2376
Use more PGO counters
Kobzol May 22, 2023
282dec1
Set counters using LLVM CLI flags
Kobzol May 22, 2023
aeb7b54
Try different profile format name
Kobzol May 23, 2023
21d4c2d
Try using flags directly
Kobzol May 23, 2023
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36 changes: 31 additions & 5 deletions src/bootstrap/llvm.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -331,15 +331,34 @@ impl Step for Llvm {
// This flag makes sure `FileCheck` is copied in the final binaries directory.
cfg.define("LLVM_INSTALL_UTILS", "ON");

let mut cxxflags: Vec<String> = Vec::new();
if builder.config.llvm_profile_generate {
cfg.define("LLVM_BUILD_INSTRUMENTED", "IR");
if let Ok(llvm_profile_dir) = std::env::var("LLVM_PROFILE_DIR") {
cfg.define("LLVM_PROFILE_DATA_DIR", llvm_profile_dir);
if std::env::var("LLVM_USE_CS_PGO").is_ok() {
//cfg.define("LLVM_BUILD_INSTRUMENTED", "CSIR");
cxxflags.push(format!(
"-fcs-profile-generate={}",
std::env::var("LLVM_PROFILE_DIR").unwrap()
));
//if let Ok(llvm_profile_dir) = std::env::var("LLVM_PROFILE_DIR") {
// cfg.define("LLVM_CSPROFILE_DATA_DIR", llvm_profile_dir);
//}
cxxflags.push("-mllvm".to_string());
cxxflags.push("-vp-counters-per-site=10".to_string());
} else {
//cfg.define("LLVM_BUILD_INSTRUMENTED", "IR");
//if let Ok(llvm_profile_dir) = std::env::var("LLVM_PROFILE_DIR") {
// cfg.define("LLVM_PROFILE_DATA_DIR", llvm_profile_dir);
//}
cxxflags.push(format!(
"-fprofile-generate={}",
std::env::var("LLVM_PROFILE_DIR").unwrap()
));
}
cfg.define("LLVM_BUILD_RUNTIME", "No");
}
if let Some(path) = builder.config.llvm_profile_use.as_ref() {
cfg.define("LLVM_PROFDATA_FILE", &path);
// cfg.define("LLVM_PROFDATA_FILE", &path);
cxxflags.push(format!("-fprofile-use={path}"));
}
if builder.config.llvm_bolt_profile_generate
|| builder.config.llvm_bolt_profile_use.is_some()
Expand Down Expand Up @@ -474,7 +493,14 @@ impl Step for Llvm {
cfg.define("LLVM_VERSION_SUFFIX", suffix);
}

configure_cmake(builder, target, &mut cfg, true, ldflags, &[]);
configure_cmake(
builder,
target,
&mut cfg,
true,
ldflags,
&cxxflags.iter().map(|s| s.as_str()).collect::<Vec<_>>(),
);
configure_llvm(builder, target, &mut cfg);

for (key, val) in &builder.config.llvm_build_config {
Expand Down
61 changes: 57 additions & 4 deletions src/ci/stage-build.py
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@

LLVM_BOLT_CRATES = LLVM_PGO_CRATES


class Pipeline:
# Paths
def checkout_path(self) -> Path:
Expand Down Expand Up @@ -86,6 +87,9 @@ def opt_artifacts(self) -> Path:
def llvm_profile_dir_root(self) -> Path:
return self.opt_artifacts() / "llvm-pgo"

def llvm_profile_merged_file_intermediate(self) -> Path:
return self.opt_artifacts() / "llvm-pgo-intermediate.profdata"

def llvm_profile_merged_file(self) -> Path:
return self.opt_artifacts() / "llvm-pgo.profdata"

Expand Down Expand Up @@ -450,6 +454,7 @@ def cmd(
)
return subprocess.run(args, env=environment, check=True)


class BenchmarkRunner:
def run_rustc(self, pipeline: Pipeline):
raise NotImplementedError
Expand All @@ -460,6 +465,7 @@ def run_llvm(self, pipeline: Pipeline):
def run_bolt(self, pipeline: Pipeline):
raise NotImplementedError


class DefaultBenchmarkRunner(BenchmarkRunner):
def run_rustc(self, pipeline: Pipeline):
# Here we're profiling the `rustc` frontend, so we also include `Check`.
Expand All @@ -473,6 +479,7 @@ def run_rustc(self, pipeline: Pipeline):
LLVM_PROFILE_FILE=str(pipeline.rustc_profile_template_path())
)
)

def run_llvm(self, pipeline: Pipeline):
run_compiler_benchmarks(
pipeline,
Expand All @@ -489,6 +496,7 @@ def run_bolt(self, pipeline: Pipeline):
crates=LLVM_BOLT_CRATES
)


def run_compiler_benchmarks(
pipeline: Pipeline,
profiles: List[str],
Expand Down Expand Up @@ -622,7 +630,7 @@ def gather_llvm_profiles(pipeline: Pipeline, runner: BenchmarkRunner):

runner.run_llvm(pipeline)

profile_path = pipeline.llvm_profile_merged_file()
profile_path = pipeline.llvm_profile_merged_file_intermediate()
LOGGER.info(f"Merging LLVM PGO profiles to {profile_path}")
cmd([
pipeline.downloaded_llvm_dir() / "bin" / "llvm-profdata",
Expand All @@ -642,13 +650,37 @@ def gather_llvm_profiles(pipeline: Pipeline, runner: BenchmarkRunner):
delete_directory(pipeline.llvm_profile_dir_root())


def gather_llvm_cs_profiles(pipeline: Pipeline, runner: BenchmarkRunner):
LOGGER.info("Running benchmarks with CS PGO instrumented LLVM")

runner.run_llvm(pipeline)

profile_path = pipeline.llvm_profile_merged_file()
LOGGER.info(f"Merging LLVM CS PGO profiles to {profile_path}")
cmd([
pipeline.downloaded_llvm_dir() / "bin" / "llvm-profdata",
"merge",
"-o", profile_path,
pipeline.llvm_profile_dir_root(),
pipeline.llvm_profile_merged_file_intermediate()
])

LOGGER.info("LLVM CS PGO statistics")
LOGGER.info(f"{profile_path}: {format_bytes(get_path_size(profile_path))}")
LOGGER.info(
f"{pipeline.llvm_profile_dir_root()}: {format_bytes(get_path_size(pipeline.llvm_profile_dir_root()))}")
LOGGER.info(f"Profile file count: {count_files(pipeline.llvm_profile_dir_root())}")

# We don't need the individual .profraw files now that they have been merged
# into a final .profdata
delete_directory(pipeline.llvm_profile_dir_root())


def gather_rustc_profiles(pipeline: Pipeline, runner: BenchmarkRunner):
LOGGER.info("Running benchmarks with PGO instrumented rustc")


runner.run_rustc(pipeline)


profile_path = pipeline.rustc_profile_merged_file()
LOGGER.info(f"Merging Rustc PGO profiles to {profile_path}")
cmd([
Expand Down Expand Up @@ -778,7 +810,7 @@ def execute_build_pipeline(timer: Timer, pipeline: Pipeline, runner: BenchmarkRu
build_rustc(pipeline, args=[
"--llvm-profile-generate"
], env=dict(
LLVM_PROFILE_DIR=str(pipeline.llvm_profile_dir_root() / "prof-%p")
LLVM_PROFILE_DIR=str(pipeline.llvm_profile_dir_root() / "profiles")
))
record_metrics(pipeline, rustc_build)

Expand All @@ -787,6 +819,26 @@ def execute_build_pipeline(timer: Timer, pipeline: Pipeline, runner: BenchmarkRu
print_free_disk_space(pipeline)

clear_llvm_files(pipeline)

# Stage 1b: Build rustc + CS PGO instrumented LLVM
with timer.section("Stage 1b (LLVM CS PGO)") as stage1b:
with stage1b.section("Build rustc and LLVM") as rustc_build:
build_rustc(pipeline, args=[
"--llvm-profile-generate",
"--llvm-profile-use",
pipeline.llvm_profile_merged_file_intermediate()
], env=dict(
LLVM_USE_CS_PGO="1",
LLVM_PROFILE_DIR=str(pipeline.llvm_profile_dir_root() / "profiles2"),
))
record_metrics(pipeline, rustc_build)

with stage1b.section("Gather profiles"):
gather_llvm_cs_profiles(pipeline, runner)
print_free_disk_space(pipeline)

clear_llvm_files(pipeline)

final_build_args += [
"--llvm-profile-use",
pipeline.llvm_profile_merged_file()
Expand Down Expand Up @@ -865,6 +917,7 @@ def run(runner: BenchmarkRunner):

print_binary_sizes(pipeline)


if __name__ == "__main__":
runner = DefaultBenchmarkRunner()
run(runner)