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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.h
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.h')
-rw-r--r--trace.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/trace.h b/trace.h
index 4b893a55cf..c843e681a7 100644
--- a/trace.h
+++ b/trace.h
@@ -31,6 +31,14 @@ extern void trace_argv_printf(const char **argv, const char *format, ...);
extern void trace_strbuf(struct trace_key *key, const struct strbuf *data);
+/* Prints elapsed time (in nanoseconds) if GIT_TRACE_PERFORMANCE is enabled. */
+__attribute__((format (printf, 2, 3)))
+extern void trace_performance(uint64_t nanos, const char *format, ...);
+
+/* Prints elapsed time since 'start' if GIT_TRACE_PERFORMANCE is enabled. */
+__attribute__((format (printf, 2, 3)))
+extern void trace_performance_since(uint64_t start, const char *format, ...);
+
#else
/*
@@ -79,6 +87,13 @@ extern void trace_strbuf(struct trace_key *key, const struct strbuf *data);
#define trace_strbuf(key, data) \
trace_strbuf_fl(TRACE_CONTEXT, __LINE__, key, data)
+#define trace_performance(nanos, ...) \
+ trace_performance_fl(TRACE_CONTEXT, __LINE__, nanos, __VA_ARGS__)
+
+#define trace_performance_since(start, ...) \
+ trace_performance_fl(TRACE_CONTEXT, __LINE__, getnanotime() - (start), \
+ __VA_ARGS__)
+
/* backend functions, use non-*fl macros instead */
__attribute__((format (printf, 4, 5)))
extern void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
@@ -88,6 +103,9 @@ extern void trace_argv_printf_fl(const char *file, int line, const char **argv,
const char *format, ...);
extern void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
const struct strbuf *data);
+__attribute__((format (printf, 4, 5)))
+extern void trace_performance_fl(const char *file, int line,
+ uint64_t nanos, const char *fmt, ...);
#endif /* HAVE_VARIADIC_MACROS */