Add trace_performance and trace_performance_since macros that print file
name, line number, time and an optional printf-formatted text to the file
specified in environment variable GIT_TRACE_PERFORMANCE.
Unless enabled via GIT_TRACE_PERFORMANCE, these macros have no noticeable
impact on performance, so that test code may be shipped in release builds.
MSVC: variadic macros (__VA_ARGS__) require VC++ 2005 or newer.
Simple use case (measure one code section):
uint64_t start = getnanotime();
/* code section to measure */
trace_performance_since(start, "foobar");
Medium use case (measure consecutive code sections):
uint64_t start = getnanotime();
/* first code section to measure */
start = trace_performance_since(start, "first foobar");
/* second code section to measure */
trace_performance_since(start, "second 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 <[email protected]>
---
cache.h | 18 ++++++++++++++++++
trace.c | 40 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 58 insertions(+)
diff --git a/cache.h b/cache.h
index 48fc616..cb856d9 100644
--- a/cache.h
+++ b/cache.h
@@ -1363,6 +1363,24 @@ __attribute__((format (printf, 2, 3)))
extern void trace_printf_key(const char *key, const char *fmt, ...);
extern void trace_strbuf(const char *key, const struct strbuf *buf);
extern uint64_t getnanotime(void);
+__attribute__((format (printf, 4, 5)))
+extern uint64_t trace_performance_file_line(const char *file, int lineno,
+ uint64_t nanos, const char *fmt, ...);
+
+/*
+ * Prints specified time (in nanoseconds) if GIT_TRACE_PERFORMANCE is enabled.
+ * Returns current time in nanoseconds.
+ */
+#define trace_performance(nanos, ...) \
+ trace_performance_file_line(__FILE__, __LINE__, nanos, __VA_ARGS__)
+
+/*
+ * Prints time since 'start' if GIT_TRACE_PERFORMANCE is enabled.
+ * Returns current time in nanoseconds.
+ */
+#define trace_performance_since(start, ...) \
+ trace_performance_file_line(__FILE__, __LINE__, \
+ getnanotime() - (start), __VA_ARGS__)
void packet_trace_identity(const char *prog);
diff --git a/trace.c b/trace.c
index 3d72084..1b1903b 100644
--- a/trace.c
+++ b/trace.c
@@ -269,3 +269,43 @@ inline uint64_t getnanotime(void)
return now;
}
}
+
+static const char *GIT_TRACE_PERFORMANCE = "GIT_TRACE_PERFORMANCE";
+
+static inline int trace_want_performance(void)
+{
+ static int enabled = -1;
+ if (enabled < 0)
+ enabled = trace_want(GIT_TRACE_PERFORMANCE);
+ return enabled;
+}
+
+/*
+ * Prints performance data if environment variable GIT_TRACE_PERFORMANCE is
+ * set, otherwise a NOOP. Returns the current time in nanoseconds.
+ */
+__attribute__((format (printf, 4, 5)))
+uint64_t trace_performance_file_line(const char *file, int lineno,
+ uint64_t nanos, const char *fmt, ...)
+{
+ struct strbuf buf = STRBUF_INIT;
+ va_list args;
+
+ if (!trace_want_performance())
+ return 0;
+
+ strbuf_addf(&buf, "performance: at %s:%i, time: %.9f s", file, lineno,
+ (double) nanos / 1000000000);
+
+ if (fmt && *fmt) {
+ strbuf_addstr(&buf, ": ");
+ va_start(args, fmt);
+ strbuf_vaddf(&buf, fmt, args);
+ va_end(args);
+ }
+ strbuf_addch(&buf, '\n');
+
+ trace_strbuf(GIT_TRACE_PERFORMANCE, &buf);
+ strbuf_release(&buf);
+ return getnanotime();
+}
--
1.9.2.msysgit.0.493.g47a82c3
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