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authorDenys Vlasenko <vda.linux@googlemail.com>2016-04-03 16:55:03 +0200
committerDenys Vlasenko <vda.linux@googlemail.com>2016-04-03 16:55:03 +0200
commit46b494635e6ef54e282749d2c65dd1922b167931 (patch)
treee6157bc2c346de1d9fdeb4eef958c615f0248961
parentbc14f4d13d3cf1d43ae809d641e29174662cd1e4 (diff)
downloadbusybox-46b494635e6ef54e282749d2c65dd1922b167931.tar.gz
libbb: speed up error_msg functions
function old new delta bb_verror_msg 386 466 +80 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--libbb/verror_msg.c29
1 files changed, 25 insertions, 4 deletions
diff --git a/libbb/verror_msg.c b/libbb/verror_msg.c
index 0ef2a311f..22c30357b 100644
--- a/libbb/verror_msg.c
+++ b/libbb/verror_msg.c
@@ -20,6 +20,7 @@ const char *msg_eol = "\n";
void FAST_FUNC bb_verror_msg(const char *s, va_list p, const char* strerr)
{
char *msg, *msg1;
+ char stack_msg[80];
int applet_len, strerr_len, msgeol_len, used;
if (!logmode)
@@ -28,6 +29,27 @@ void FAST_FUNC bb_verror_msg(const char *s, va_list p, const char* strerr)
if (!s) /* nomsg[_and_die] uses NULL fmt */
s = ""; /* some libc don't like printf(NULL) */
+ applet_len = strlen(applet_name) + 2; /* "applet: " */
+ strerr_len = strerr ? strlen(strerr) : 0;
+ msgeol_len = strlen(msg_eol);
+
+ /* This costs ~90 bytes of code, but avoids costly
+ * malloc()[in vasprintf]+realloc()+memmove()+free() in 99% of cases.
+ * ~40% speedup.
+ */
+ if ((int)sizeof(stack_msg) - applet_len > 0) {
+ va_list p2;
+
+ /* It is not portable to use va_list twice, need to va_copy it */
+ va_copy(p2, p);
+ used = vsnprintf(stack_msg + applet_len, (int)sizeof(stack_msg) - applet_len, s, p2);
+ va_end(p2);
+ msg = stack_msg;
+ used += applet_len;
+ if (used < (int)sizeof(stack_msg) - 3 - msgeol_len - strerr_len)
+ goto add_pfx_and_sfx;
+ }
+
used = vasprintf(&msg, s, p);
if (used < 0)
return;
@@ -37,9 +59,6 @@ void FAST_FUNC bb_verror_msg(const char *s, va_list p, const char* strerr)
* This is needed for e.g. httpd logging, when multiple
* children can produce log messages simultaneously. */
- applet_len = strlen(applet_name) + 2; /* "applet: " */
- strerr_len = strerr ? strlen(strerr) : 0;
- msgeol_len = strlen(msg_eol);
/* can't use xrealloc: it calls error_msg on failure,
* that may result in a recursion */
/* +3 is for ": " before strerr and for terminating NUL */
@@ -52,6 +71,7 @@ void FAST_FUNC bb_verror_msg(const char *s, va_list p, const char* strerr)
/* TODO: maybe use writev instead of memmoving? Need full_writev? */
memmove(msg + applet_len, msg, used);
used += applet_len;
+ add_pfx_and_sfx:
strcpy(msg, applet_name);
msg[applet_len - 2] = ':';
msg[applet_len - 1] = ' ';
@@ -76,7 +96,8 @@ void FAST_FUNC bb_verror_msg(const char *s, va_list p, const char* strerr)
syslog(syslog_level, "%s", msg + applet_len);
}
#endif
- free(msg);
+ if (msg != stack_msg)
+ free(msg);
}
#ifdef VERSION_WITH_WRITEV