[logging] Minor performance tweak
2007-04-29 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
* log.c: (quagga_timestamp) Optimize the subsecond timestamp generation.
diff --git a/lib/ChangeLog b/lib/ChangeLog
index 3e515f8..f8fdd11 100644
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,3 +1,7 @@
+2007-04-29 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
+
+ * log.c: (quagga_timestamp) Optimize the subsecond timestamp generation.
+
2007-04-28 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
* command.c: (config_write_host) Save "log timestamp precision"
diff --git a/lib/log.c b/lib/log.c
index 7668222..21bf3f2 100644
--- a/lib/log.c
+++ b/lib/log.c
@@ -100,18 +100,25 @@
(buflen > cache.len+1+timestamp_precision))
{
/* should we worry about locale issues? */
- long divisor = 100000;
- char *p = buf+cache.len;
- *p++ = '.';
+ static const int divisor[] = {0, 100000, 10000, 1000, 100, 10, 1};
+ int prec;
+ char *p = buf+cache.len+1+(prec = timestamp_precision);
+ *p-- = '\0';
+ while (prec > 6)
+ /* this is unlikely to happen, but protect anyway */
+ {
+ *p-- = '0';
+ prec--;
+ }
+ clock.tv_usec /= divisor[prec];
do
{
- *p++ = '0'+(clock.tv_usec/divisor);
- clock.tv_usec %= divisor;
- divisor /= 10;
+ *p-- = '0'+(clock.tv_usec % 10);
+ clock.tv_usec /= 10;
}
- while (--timestamp_precision > 0);
- *p = '\0';
- return p-buf;
+ while (--prec > 0);
+ *p = '.';
+ return cache.len+1+timestamp_precision;
}
buf[cache.len] = '\0';
return cache.len;