Henrik , Neil , Thanks a lot for your response !! I got several times sent mail failure notice , so I resend it again . hope you could get it . Acctually , I tried to use Linux OS default malloc, gnu malloc , dlmalloc, dlmalloc could help me get the best performance among the three different malloc . I checked all my mgr:info log , when I set the cache_mem to different size , the stroe entries are different too . When the cache memory is 4GB , the Store Entries are ~519396 When the cache memory is 6 GB , the StoreEntries are ~776836 When the cache memory is 8 GB , the StoreEntries are ~1026097 The average size of the stored objects almost ~8KB, so I am not sure whether such problem was caused by large objects . In the mean time , the request rate to the squid was about 2500 requests per second . I checked a hash_lookup method , If in the worst cases in 8G scenario,it looks like almost 2 times of hash keys will be traversed to get the storeEntry than in 4 G scenario. Is it a possible reason ? Or any other suggestion ? void * hash_lookup(hash_table * hid, const void *k) { hash_link *walker; int b; assert(k !=3D NULL); b =3D hid->hash(k, hid->size); *for (walker =3D hid->buckets[b]; walker !=3D NULL; walker =3D walker->= next*) { /* strcmp of NULL is a SEGV */ if (NULL =3D=3D walker->key) return NULL; if ((hid->cmp) (k, walker->key) =3D=3D 0) return (walker); assert(walker !=3D walker->next); } return NULL; Thanks , -Arkin On Sat, Jun 14, 2008 at 5:25 PM, Henrik Nordstrom <henrik@xxxxxxxxxxxxxxxxxxx> wrote: > On lör, 2008-06-14 at 14:10 +0800, Arkin, Y wrote: > >> Configuration: >> ./configure --enable-dlmalloc ...etc... > > Hmm.. don't use --enable-dlmalloc if you have more than 2 GB of memory, > or at all if you have a reasonably modern OS.. (i.e. almost anything > released this millenium) > >> one Squid instance is running on the cache server , >> squid .conf : >> cache_mem 8192 MB >> maximum_object_size_in_memory 2048 KB > > This may be the culpit. Squid-2 is very very poor at handling large > objects in memory, wasting exponential amount of CPU the larger the > object is.. > > This is fixed in Squid-3. > > Regards > Henrik >