Merge branch 'gk/tracing-optimization'

The tracing infrastructure has been optimized for cases where no
tracing is requested.

* gk/tracing-optimization:
trace: improve performance while category is disabled
trace: remove trace key normalization

diff --git a/trace.c b/trace.c
index cb1293ed33e16f605f8ac99336f040275c7bda7a..b7530b51a9e4d20825d42fcfd2a5dd389ad3b44e 100644 (file)
--- a/trace.c
+++ b/trace.c
@@ -24,26 +24,14 @@
 #include "cache.h"
 #include "quote.h"
 
-/*
- * "Normalize" a key argument by converting NULL to our trace_default,
- * and otherwise passing through the value. All caller-facing functions
- * should normalize their inputs in this way, though most get it
- * for free by calling get_trace_fd() (directly or indirectly).
- */
-static void normalize_trace_key(struct trace_key **key)
-{
-       static struct trace_key trace_default = { "GIT_TRACE" };
-       if (!*key)
-               *key = &trace_default;
-}
+struct trace_key trace_default_key = { "GIT_TRACE", 0, 0, 0 };
+struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
 
 /* Get a trace file descriptor from "key" env variable. */
 static int get_trace_fd(struct trace_key *key)
 {
        const char *trace;
 
-       normalize_trace_key(&key);
-
        /* don't open twice */
        if (key->initialized)
                return key->fd;
@@ -81,8 +69,6 @@ static int get_trace_fd(struct trace_key *key)
 
 void trace_disable(struct trace_key *key)
 {
-       normalize_trace_key(&key);
-
        if (key->need_close)
                close(key->fd);
        key->fd = 0;
@@ -128,7 +114,6 @@ static int prepare_trace_line(const char *file, int line,
 static void trace_write(struct trace_key *key, const void *buf, unsigned len)
 {
        if (write_in_full(get_trace_fd(key), buf, len) < 0) {
-               normalize_trace_key(&key);
                warning("unable to write trace for %s: %s",
                        key->key, strerror(errno));
                trace_disable(key);
@@ -167,13 +152,13 @@ static void trace_argv_vprintf_fl(const char *file, int line,
 {
        struct strbuf buf = STRBUF_INIT;
 
-       if (!prepare_trace_line(file, line, NULL, &buf))
+       if (!prepare_trace_line(file, line, &trace_default_key, &buf))
                return;
 
        strbuf_vaddf(&buf, format, ap);
 
        sq_quote_argv(&buf, argv, 0);
-       print_trace_line(NULL, &buf);
+       print_trace_line(&trace_default_key, &buf);
 }
 
 void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
@@ -188,8 +173,6 @@ 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)
@@ -215,7 +198,7 @@ void trace_printf(const char *format, ...)
 {
        va_list ap;
        va_start(ap, format);
-       trace_vprintf_fl(NULL, 0, NULL, format, ap);
+       trace_vprintf_fl(NULL, 0, &trace_default_key, format, ap);
        va_end(ap);
 }
 

diff --git a/trace.h b/trace.h
index 179b249c597125ac8ad3ed2d0c0e6b00a94773eb..88055abef7342ee638f6597a6628bcdf4baeace9 100644 (file)
--- a/trace.h
+++ b/trace.h
@@ -11,7 +11,10 @@ struct trace_key {
        unsigned int  need_close : 1;
 };
 
+extern struct trace_key trace_default_key;
+
 #define TRACE_KEY_INIT(name) { "GIT_TRACE_" #name, 0, 0, 0 }
+extern struct trace_key trace_perf_key;
 
 extern void trace_repo_setup(const char *prefix);
 extern int trace_want(struct trace_key *key);
@@ -77,24 +80,42 @@ extern void trace_performance_since(uint64_t start, const char *format, ...);
  * comma, but this is non-standard.
  */
 
-#define trace_printf(...) \
-       trace_printf_key_fl(TRACE_CONTEXT, __LINE__, NULL, __VA_ARGS__)
-
-#define trace_printf_key(key, ...) \
-       trace_printf_key_fl(TRACE_CONTEXT, __LINE__, key, __VA_ARGS__)
-
-#define trace_argv_printf(argv, ...) \
-       trace_argv_printf_fl(TRACE_CONTEXT, __LINE__, argv, __VA_ARGS__)
-
-#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__)
+#define trace_printf_key(key, ...)                                         \
+       do {                                                                \
+               if (trace_pass_fl(key))                                     \
+                       trace_printf_key_fl(TRACE_CONTEXT, __LINE__, key,   \
+                                           __VA_ARGS__);                   \
+       } while (0)
+
+#define trace_printf(...) trace_printf_key(&trace_default_key, __VA_ARGS__)
+
+#define trace_argv_printf(argv, ...)                                       \
+       do {                                                                \
+               if (trace_pass_fl(&trace_default_key))                      \
+                       trace_argv_printf_fl(TRACE_CONTEXT, __LINE__,       \
+                                           argv, __VA_ARGS__);             \
+       } while (0)
+
+#define trace_strbuf(key, data)                                                    \
+       do {                                                                \
+               if (trace_pass_fl(key))                                     \
+                       trace_strbuf_fl(TRACE_CONTEXT, __LINE__, key, data);\
+       } while (0)
+
+#define trace_performance(nanos, ...)                                      \
+       do {                                                                \
+               if (trace_pass_fl(&trace_perf_key))                         \
+                       trace_performance_fl(TRACE_CONTEXT, __LINE__, nanos,\
+                                            __VA_ARGS__);                  \
+       } while (0)
+
+#define trace_performance_since(start, ...)                                \
+       do {                                                                \
+               if (trace_pass_fl(&trace_perf_key))                         \
+                       trace_performance_fl(TRACE_CONTEXT, __LINE__,       \
+                                            getnanotime() - (start),       \
+                                            __VA_ARGS__);                  \
+       } while (0)
 
 /* backend functions, use non-*fl macros instead */
 __attribute__((format (printf, 4, 5)))
@@ -108,6 +129,10 @@ extern void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
 __attribute__((format (printf, 4, 5)))
 extern void trace_performance_fl(const char *file, int line,
                                 uint64_t nanos, const char *fmt, ...);
+static inline int trace_pass_fl(struct trace_key *key)
+{
+       return key->fd || !key->initialized;
+}
 
 #endif /* HAVE_VARIADIC_MACROS */