From dd7c5a00cb1cc5dbf5f661bb72c8e7d237031953 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jakub=20Ber=C3=A1nek?= Date: Mon, 2 Oct 2023 21:11:15 +0200 Subject: [PATCH] Optimize `librustc_driver.so` with BOLT --- src/tools/opt-dist/src/bolt.rs | 14 +++++--- src/tools/opt-dist/src/exec.rs | 4 +-- src/tools/opt-dist/src/main.rs | 56 ++++++++++++++++++++---------- src/tools/opt-dist/src/training.rs | 53 ++++++++++++++++++---------- 4 files changed, 84 insertions(+), 43 deletions(-) diff --git a/src/tools/opt-dist/src/bolt.rs b/src/tools/opt-dist/src/bolt.rs index cf9f4fabcec..f694c08f9b9 100644 --- a/src/tools/opt-dist/src/bolt.rs +++ b/src/tools/opt-dist/src/bolt.rs @@ -1,14 +1,14 @@ use anyhow::Context; use crate::exec::cmd; -use crate::training::LlvmBoltProfile; +use crate::training::BoltProfile; use camino::{Utf8Path, Utf8PathBuf}; use crate::utils::io::copy_file; /// Instruments an artifact at the given `path` (in-place) with BOLT and then calls `func`. /// After this function finishes, the original file will be restored. -pub fn with_bolt_instrumented anyhow::Result, R>( +pub fn with_bolt_instrumented anyhow::Result, R>( path: &Utf8Path, func: F, ) -> anyhow::Result { @@ -20,10 +20,16 @@ pub fn with_bolt_instrumented anyhow::Result, R>( let instrumented_path = tempfile::NamedTempFile::new()?.into_temp_path(); + let profile_dir = + tempfile::TempDir::new().context("Could not create directory for BOLT profiles")?; + let profile_prefix = profile_dir.path().join("prof.fdata"); + let profile_prefix = Utf8Path::from_path(&profile_prefix).unwrap(); + // Instrument the original file with BOLT, saving the result into `instrumented_path` cmd(&["llvm-bolt"]) .arg("-instrument") .arg(path) + .arg(&format!("--instrumentation-file={profile_prefix}")) // Make sure that each process will write its profiles into a separate file .arg("--instrumentation-file-append-pid") .arg("-o") @@ -36,11 +42,11 @@ pub fn with_bolt_instrumented anyhow::Result, R>( // Run the function that will make use of the instrumented artifact. // The original file will be restored when `_backup_file` is dropped. - func() + func(profile_prefix) } /// Optimizes the file at `path` with BOLT in-place using the given `profile`. -pub fn bolt_optimize(path: &Utf8Path, profile: &LlvmBoltProfile) -> anyhow::Result<()> { +pub fn bolt_optimize(path: &Utf8Path, profile: &BoltProfile) -> anyhow::Result<()> { // Copy the artifact to a new location, so that we do not use the same input and output file. // BOLT cannot handle optimizing when the input and output is the same file, because it performs // in-place patching. diff --git a/src/tools/opt-dist/src/exec.rs b/src/tools/opt-dist/src/exec.rs index 04e0184528a..f07bd5f9fce 100644 --- a/src/tools/opt-dist/src/exec.rs +++ b/src/tools/opt-dist/src/exec.rs @@ -1,7 +1,7 @@ use crate::environment::Environment; use crate::metrics::{load_metrics, record_metrics}; use crate::timer::TimerSection; -use crate::training::{LlvmBoltProfile, LlvmPGOProfile, RustcPGOProfile}; +use crate::training::{BoltProfile, LlvmPGOProfile, RustcPGOProfile}; use camino::{Utf8Path, Utf8PathBuf}; use std::collections::BTreeMap; use std::fs::File; @@ -159,7 +159,7 @@ pub fn with_llvm_bolt_ldflags(mut self) -> Self { self } - pub fn with_bolt_profile(mut self, profile: LlvmBoltProfile) -> Self { + pub fn with_bolt_profile(mut self, profile: BoltProfile) -> Self { self.cmd = self.cmd.arg("--reproducible-artifact").arg(profile.0.as_str()); self } diff --git a/src/tools/opt-dist/src/main.rs b/src/tools/opt-dist/src/main.rs index 03a1912f5ce..e6829b79f87 100644 --- a/src/tools/opt-dist/src/main.rs +++ b/src/tools/opt-dist/src/main.rs @@ -12,7 +12,10 @@ use crate::exec::{cmd, Bootstrap}; use crate::tests::run_tests; use crate::timer::Timer; -use crate::training::{gather_llvm_bolt_profiles, gather_llvm_profiles, gather_rustc_profiles}; +use crate::training::{ + gather_bolt_profiles, gather_llvm_profiles, gather_rustc_profiles, llvm_benchmarks, + rustc_benchmarks, +}; use crate::utils::artifact_size::print_binary_sizes; use crate::utils::io::{copy_directory, move_directory, reset_directory}; use crate::utils::{ @@ -246,13 +249,13 @@ fn execute_pipeline( Ok(profile) })?; - let llvm_bolt_profile = if env.use_bolt() { + let bolt_profiles = if env.use_bolt() { // Stage 3: Build BOLT instrumented LLVM // We build a PGO optimized LLVM in this step, then instrument it with BOLT and gather BOLT profiles. // Note that we don't remove LLVM artifacts after this step, so that they are reused in the final dist build. // BOLT instrumentation is performed "on-the-fly" when the LLVM library is copied to the sysroot of rustc, // therefore the LLVM artifacts on disk are not "tainted" with BOLT instrumentation and they can be reused. - timer.section("Stage 3 (LLVM BOLT)", |stage| { + timer.section("Stage 3 (BOLT)", |stage| { stage.section("Build PGO optimized LLVM", |stage| { Bootstrap::build(env) .with_llvm_bolt_ldflags() @@ -261,16 +264,17 @@ fn execute_pipeline( .run(stage) })?; - // Find the path to the `libLLVM.so` file - let llvm_lib = io::find_file_in_dir( - &env.build_artifacts().join("stage2").join("lib"), - "libLLVM", - ".so", - )?; + let libdir = env.build_artifacts().join("stage2").join("lib"); + let llvm_lib = io::find_file_in_dir(&libdir, "libLLVM", ".so")?; - // Instrument it and gather profiles - let profile = with_bolt_instrumented(&llvm_lib, || { - stage.section("Gather profiles", |_| gather_llvm_bolt_profiles(env)) + log::info!("Optimizing {llvm_lib} with BOLT"); + + // FIXME(kobzol: try gather profiles together, at once for LLVM and rustc + // Instrument the libraries and gather profiles + let llvm_profile = with_bolt_instrumented(&llvm_lib, |llvm_profile_dir| { + stage.section("Gather profiles", |_| { + gather_bolt_profiles(env, "LLVM", llvm_benchmarks(env), llvm_profile_dir) + }) })?; print_free_disk_space()?; @@ -279,13 +283,29 @@ fn execute_pipeline( // the final dist build. However, when BOLT optimizes an artifact, it does so *in-place*, // therefore it will actually optimize all the hard links, which means that the final // packaged `libLLVM.so` file *will* be BOLT optimized. - bolt_optimize(&llvm_lib, &profile).context("Could not optimize LLVM with BOLT")?; + bolt_optimize(&llvm_lib, &llvm_profile).context("Could not optimize LLVM with BOLT")?; + + let rustc_lib = io::find_file_in_dir(&libdir, "librustc_driver", ".so")?; + + log::info!("Optimizing {rustc_lib} with BOLT"); + + // Instrument it and gather profiles + let rustc_profile = with_bolt_instrumented(&rustc_lib, |rustc_profile_dir| { + stage.section("Gather profiles", |_| { + gather_bolt_profiles(env, "rustc", rustc_benchmarks(env), rustc_profile_dir) + }) + })?; + print_free_disk_space()?; + + // Now optimize the library with BOLT. + bolt_optimize(&rustc_lib, &rustc_profile) + .context("Could not optimize rustc with BOLT")?; // LLVM is not being cleared here, we want to use the BOLT-optimized LLVM - Ok(Some(profile)) + Ok(vec![llvm_profile, rustc_profile]) })? } else { - None + vec![] }; let mut dist = Bootstrap::dist(env, &dist_args) @@ -293,13 +313,13 @@ fn execute_pipeline( .rustc_pgo_optimize(&rustc_pgo_profile) .avoid_rustc_rebuild(); - if let Some(llvm_bolt_profile) = llvm_bolt_profile { - dist = dist.with_bolt_profile(llvm_bolt_profile); + for bolt_profile in bolt_profiles { + dist = dist.with_bolt_profile(bolt_profile); } // Final stage: Assemble the dist artifacts // The previous PGO optimized rustc build and PGO optimized LLVM builds should be reused. - timer.section("Stage 4 (final build)", |stage| dist.run(stage))?; + timer.section("Stage 5 (final build)", |stage| dist.run(stage))?; // After dist has finished, run a subset of the test suite on the optimized artifacts to discover // possible regressions. diff --git a/src/tools/opt-dist/src/training.rs b/src/tools/opt-dist/src/training.rs index 274f4cea0ab..46040e32a03 100644 --- a/src/tools/opt-dist/src/training.rs +++ b/src/tools/opt-dist/src/training.rs @@ -27,8 +27,6 @@ "bitmaps-3.1.0", ]; -const LLVM_BOLT_CRATES: &[&str] = LLVM_PGO_CRATES; - fn init_compiler_benchmarks( env: &Environment, profiles: &[&str], @@ -113,6 +111,14 @@ fn log_profile_stats( Ok(()) } +pub fn llvm_benchmarks(env: &Environment) -> CmdBuilder { + init_compiler_benchmarks(env, &["Debug", "Opt"], &["Full"], LLVM_PGO_CRATES) +} + +pub fn rustc_benchmarks(env: &Environment) -> CmdBuilder { + init_compiler_benchmarks(env, &["Check", "Debug", "Opt"], &["All"], RUSTC_PGO_CRATES) +} + pub struct LlvmPGOProfile(pub Utf8PathBuf); pub fn gather_llvm_profiles( @@ -122,9 +128,7 @@ pub fn gather_llvm_profiles( log::info!("Running benchmarks with PGO instrumented LLVM"); with_log_group("Running benchmarks", || { - init_compiler_benchmarks(env, &["Debug", "Opt"], &["Full"], LLVM_PGO_CRATES) - .run() - .context("Cannot gather LLVM PGO profiles") + llvm_benchmarks(env).run().context("Cannot gather LLVM PGO profiles") })?; let merged_profile = env.artifact_dir().join("llvm-pgo.profdata"); @@ -157,7 +161,7 @@ pub fn gather_rustc_profiles( // Here we're profiling the `rustc` frontend, so we also include `Check`. // The benchmark set includes various stress tests that put the frontend under pressure. with_log_group("Running benchmarks", || { - init_compiler_benchmarks(env, &["Check", "Debug", "Opt"], &["All"], RUSTC_PGO_CRATES) + rustc_benchmarks(env) .env("LLVM_PROFILE_FILE", profile_template.as_str()) .run() .context("Cannot gather rustc PGO profiles") @@ -176,23 +180,25 @@ pub fn gather_rustc_profiles( Ok(RustcPGOProfile(merged_profile)) } -pub struct LlvmBoltProfile(pub Utf8PathBuf); +pub struct BoltProfile(pub Utf8PathBuf); -pub fn gather_llvm_bolt_profiles(env: &Environment) -> anyhow::Result { - log::info!("Running benchmarks with BOLT instrumented LLVM"); +pub fn gather_bolt_profiles( + env: &Environment, + name: &str, + benchmarks: CmdBuilder, + profile_prefix: &Utf8Path, +) -> anyhow::Result { + log::info!("Running benchmarks with BOLT instrumented {name}"); with_log_group("Running benchmarks", || { - init_compiler_benchmarks(env, &["Check", "Debug", "Opt"], &["Full"], LLVM_BOLT_CRATES) - .run() - .context("Cannot gather LLVM BOLT profiles") + benchmarks.run().with_context(|| "Cannot gather {name} BOLT profiles") })?; - let merged_profile = env.artifact_dir().join("llvm-bolt.profdata"); - let profile_root = Utf8PathBuf::from("/tmp/prof.fdata"); - log::info!("Merging LLVM BOLT profiles to {merged_profile}"); + let merged_profile = env.artifact_dir().join(format!("{name}-bolt.profdata")); + log::info!("Merging {name} BOLT profiles from {profile_prefix} to {merged_profile}"); let profiles: Vec<_> = - glob::glob(&format!("{profile_root}*"))?.collect::, _>>()?; + glob::glob(&format!("{profile_prefix}*"))?.collect::, _>>()?; let mut merge_args = vec!["merge-fdata"]; merge_args.extend(profiles.iter().map(|p| p.to_str().unwrap())); @@ -204,7 +210,7 @@ pub fn gather_llvm_bolt_profiles(env: &Environment) -> anyhow::Result anyhow::Result, _>>()? .into_iter() .sum::(); - log::info!("{profile_root}: {}", humansize::format_size(size, BINARY)); + log::info!("{profile_prefix}: {}", humansize::format_size(size, BINARY)); log::info!("Profile file count: {}", profiles.len()); - Ok(LlvmBoltProfile(merged_profile)) + // Delete the gathered profiles + for profile in glob::glob(&format!("{profile_prefix}*"))?.into_iter() { + if let Ok(profile) = profile { + if let Err(error) = std::fs::remove_file(&profile) { + log::error!("Cannot delete BOLT profile {}: {error:?}", profile.display()); + } + } + } + + Ok(BoltProfile(merged_profile)) }