Obtain LRU clock in a resolution dependent way.

For testing purposes it is handy to have a very high resolution of the
LRU clock, so that it is possible to experiment with scripts running in
just a few seconds how the eviction algorithms works.

This commit allows Redis to use the cached LRU clock, or a value
computed on demand, depending on the resolution. So normally we have the
good performance of a precomputed value, and a clock that wraps in many
days using the normal resolution, but if needed, changing a define will
switch behavior to an high resolution LRU clock.
This commit is contained in:
antirez
2014-03-20 11:47:12 +01:00
parent 561e793472
commit 205c2ccc0c
4 changed files with 25 additions and 19 deletions

View File

@ -651,10 +651,11 @@ char *strEncoding(int encoding) {
/* Given an object returns the min number of seconds the object was never
* requested, using an approximated LRU algorithm. */
unsigned long long estimateObjectIdleTime(robj *o) {
if (server.lruclock >= o->lru) {
return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
unsigned long long lruclock = LRU_CLOCK();
if (lruclock >= o->lru) {
return (lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
} else {
return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
return (lruclock + (REDIS_LRU_CLOCK_MAX - o->lru)) *
REDIS_LRU_CLOCK_RESOLUTION;
}
}