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authorKarsten Blees <karsten.blees@gmail.com>2014-07-12 02:06:28 +0200
committerJunio C Hamano <gitster@pobox.com>2014-07-13 21:25:20 -0700
commit09b2c1c769a69d3ff03ee7913fa50fa05b4f5a46 (patch)
treeb7b58e6f14c3b945ba3735b2cea9590009bff0fe /trace.c
parent148d6771bf5e00aa1d7fa2221507a3dfe4c1e37f (diff)
downloadgit-09b2c1c769a69d3ff03ee7913fa50fa05b4f5a46.tar.gz
trace: add trace_performance facility to debug performance issues
Add trace_performance and trace_performance_since macros that print a duration and an optional printf-formatted text to the file specified in environment variable GIT_TRACE_PERFORMANCE. These macros, in conjunction with getnanotime(), are intended to simplify performance measurements from within the application (i.e. profiling via manual instrumentation, rather than using an external profiling tool). Unless enabled via GIT_TRACE_PERFORMANCE, these macros have no noticeable impact on performance, so that test code for well known time killers may be shipped in release builds. Alternatively, a developer could provide an additional performance patch (not meant for master) that allows reviewers to reproduce performance tests more easily, e.g. on other platforms or using their own repositories. Usage examples: Simple use case (measure one code section): uint64_t start = getnanotime(); /* code section to measure */ trace_performance_since(start, "foobar"); Complex use case (measure repetitive code sections): uint64_t t = 0; for (;;) { /* ignore */ t -= getnanotime(); /* code section to measure */ t += getnanotime(); /* ignore */ } trace_performance(t, "frotz"); Signed-off-by: Karsten Blees <blees@dcon.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'trace.c')
-rw-r--r--trace.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/trace.c b/trace.c
index b9d7272318..af64dbbcf3 100644
--- a/trace.c
+++ b/trace.c
@@ -169,6 +169,27 @@ void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
print_trace_line(key, &buf);
}
+static struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
+
+static void trace_performance_vprintf_fl(const char *file, int line,
+ uint64_t nanos, const char *format,
+ va_list ap)
+{
+ struct strbuf buf = STRBUF_INIT;
+
+ if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
+ return;
+
+ strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
+
+ if (format && *format) {
+ strbuf_addstr(&buf, ": ");
+ strbuf_vaddf(&buf, format, ap);
+ }
+
+ print_trace_line(&trace_perf_key, &buf);
+}
+
#ifndef HAVE_VARIADIC_MACROS
void trace_printf(const char *format, ...)
@@ -200,6 +221,23 @@ void trace_strbuf(const char *key, const struct strbuf *data)
trace_strbuf_fl(NULL, 0, key, data);
}
+void trace_performance(uint64_t nanos, const char *format, ...)
+{
+ va_list ap;
+ va_start(ap, format);
+ trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
+ va_end(ap);
+}
+
+void trace_performance_since(uint64_t start, const char *format, ...)
+{
+ va_list ap;
+ va_start(ap, format);
+ trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
+ format, ap);
+ va_end(ap);
+}
+
#else
void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
@@ -220,6 +258,15 @@ void trace_argv_printf_fl(const char *file, int line, const char **argv,
va_end(ap);
}
+void trace_performance_fl(const char *file, int line, uint64_t nanos,
+ const char *format, ...)
+{
+ va_list ap;
+ va_start(ap, format);
+ trace_performance_vprintf_fl(file, line, nanos, format, ap);
+ va_end(ap);
+}
+
#endif /* HAVE_VARIADIC_MACROS */