Optimize ninja -d stats
-d stats enables instrumented profiling of key functions in ninja.
However, some of those functions are invoked 6+ million times in a NOP
build of Chromium and the cost of measuring those functions dwarfs the
cost of the functions. Here is typical -d stats output for a Chromium
build:
metric count avg (us) total (ms)
.ninja parse 6580 4197.5 27619.5
canonicalize str 6240450 0.0 47.3
canonicalize path 6251390 0.0 33.5
lookup node 6339402 0.0 37.2
.ninja_log load 1 176226.0 176.2
.ninja_deps load 1 465407.0 465.4
node stat 168997 8.8 1482.9
depfile load 327 352.7 115.3
99% of the measurements are in three functions. The total measurement
cost (per ETW sampled profiling) is 700-1200 ms, which is many times
greater than the costs of the functions.
With this change typical output looks like this:
metric count avg (us) total (ms)
.ninja parse 6580 3526.3 23203.2
.ninja_log load 1 227305.0 227.3
.ninja_deps load 1 485693.0 485.7
node stat 168997 9.6 1615.0
depfile load 327 383.1 125.3
This resolves issue #1998.
diff --git a/src/state.cc b/src/state.cc
index a33d5a8..fc37c8a 100644
--- a/src/state.cc
+++ b/src/state.cc
@@ -19,7 +19,6 @@
#include "edit_distance.h"
#include "graph.h"
-#include "metrics.h"
#include "util.h"
using namespace std;
@@ -104,7 +103,6 @@
}
Node* State::LookupNode(StringPiece path) const {
- METRIC_RECORD("lookup node");
Paths::const_iterator i = paths_.find(path);
if (i != paths_.end())
return i->second;
diff --git a/src/util.cc b/src/util.cc
index 3dfa8dd..080883e 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -56,7 +56,6 @@
#endif
#include "edit_distance.h"
-#include "metrics.h"
using namespace std;
@@ -118,7 +117,6 @@
}
void CanonicalizePath(string* path, uint64_t* slash_bits) {
- METRIC_RECORD("canonicalize str");
size_t len = path->size();
char* str = 0;
if (len > 0)
@@ -138,7 +136,6 @@
void CanonicalizePath(char* path, size_t* len, uint64_t* slash_bits) {
// WARNING: this function is performance-critical; please benchmark
// any changes you make to it.
- METRIC_RECORD("canonicalize path");
if (*len == 0) {
return;
}
