[PATCH] D147815: [clang][deps] Print timing information

[Jan Svoboda via Phabricator via cfe-commits]

jansvoboda11 created this revision.
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This patch adds new `-print-timing` option to `clang-scan-deps`. It measures the wall and process time taken to scan dependencies for the compilation database. This provides more representative data compared to measuring the timing for the whole tool invocation, since that includes parsing and generating JSON files, which can be significant for larger inputs.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D147815

Files:
  clang/test/ClangScanDeps/print-timing.c
  clang/tools/clang-scan-deps/ClangScanDeps.cpp


Index: clang/tools/clang-scan-deps/ClangScanDeps.cpp
===================================================================
--- clang/tools/clang-scan-deps/ClangScanDeps.cpp
+++ clang/tools/clang-scan-deps/ClangScanDeps.cpp
@@ -19,12 +19,14 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileUtilities.h"
+#include "llvm/Support/Format.h"
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/JSON.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/ThreadPool.h"
 #include "llvm/Support/Threading.h"
+#include "llvm/Support/Timer.h"
 #include "llvm/TargetParser/Host.h"
 #include <mutex>
 #include <optional>
@@ -189,6 +191,11 @@
     llvm::cl::desc("The names of dependency targets for the dependency file"),
     llvm::cl::cat(DependencyScannerCategory));
 
+static llvm::cl::opt<bool>
+    PrintTiming("print-timing", llvm::cl::desc("Print timing information"),
+                llvm::cl::init(false),
+                llvm::cl::cat(DependencyScannerCategory));
+
 enum ResourceDirRecipeKind {
   RDRK_ModifyCompilerPath,
   RDRK_InvokeCompiler,
@@ -800,6 +807,10 @@
     llvm::outs() << "Running clang-scan-deps on " << Inputs.size()
                  << " files using " << Pool.getThreadCount() << " workers\n";
   }
+
+  llvm::Timer T;
+  T.startTimer();
+
   for (unsigned I = 0; I < Pool.getThreadCount(); ++I) {
     Pool.async([&, I]() {
       llvm::StringSet<> AlreadySeenModules;
@@ -889,6 +900,12 @@
   }
   Pool.wait();
 
+  T.stopTimer();
+  if (PrintTiming)
+    llvm::errs() << llvm::format(
+        "clang-scan-deps timing: %0.2fs wall, %0.2fs process\n",
+        T.getTotalTime().getWallTime(), T.getTotalTime().getProcessTime());
+
   if (RoundTripArgs)
     if (FD && FD->roundTripCommands(llvm::errs()))
       HadErrors = true;
Index: clang/test/ClangScanDeps/print-timing.c
===================================================================
--- /dev/null
+++ clang/test/ClangScanDeps/print-timing.c
@@ -0,0 +1,9 @@
+// RUN: rm -rf %t && mkdir %t
+// RUN: split-file %s %t
+
+// RUN: clang-scan-deps -compilation-database %t/cdb.json -print-timing > %t/result.json 2>%t/errs
+// RUN: cat %t/errs | FileCheck %s
+// CHECK: clang-scan-deps timing: {{[0-9]+}}.{{[0-9][0-9]}}s wall, {{[0-9]+}}.{{[0-9][0-9]}}s process
+
+//--- cdb.json
+[]


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