On Sun, Dec 30, 2012 at 12:50 PM, Yunkai Zhang <yunkai...@gmail.com> wrote:
> > > > On Sun, Dec 30, 2012 at 12:17 PM, John Plevyak <jplev...@acm.org> wrote: > >> Lol, If they have optimized it by removing the LRU nature, it was perhaps >> overzealous, or perhaps your workload is such that it fits within the RAM >> cache so replacement is not an issue. Without the LRU there are >> approximately the same number of buckets as objects, so replacement based >> on bucket would be largely random. Instead we can have a partitioned >> LRU, and we are probably going to have to go that route as it looks like >> lock contention in the cache is pretty bad. That's the next area I was >> thinking of looking at... >> > > > It seems that my coworker split the original one LRU queue into multiple > queues according data size(e->data->_size_index). What they do is not to > optimize LRU itself, but to reduce memory fragment caused by allocate/free > memory frequently. > > I'll send that patch to here, and hope you can give some advise. > Hi jonh: I have post the path in TS-1006<https://issues.apache.org/jira/browse/TS-1006>issue's page, there is the patch's link<https://issues.apache.org/jira/secure/attachment/12562712/0006-RamCacheLRU-split-LRU-queue-into-multiple-queues-to-.patch> . Welcome to give us some advise:) > > >> >> cheers, >> john >> >> On Sat, Dec 29, 2012 at 7:59 PM, Yunkai Zhang <yunkai...@gmail.com> >> wrote: >> >> > On Sun, Dec 30, 2012 at 1:57 AM, John Plevyak <jplev...@acm.org> wrote: >> > >> > > This code in ::put() implements the LRU, and as you can see, it uses >> the >> > > LRU data structure (i.e. simple list from most recently used to >> least): >> > > >> > > while (bytes > max_bytes) { >> > > RamCacheLRUEntry *ee = lru.dequeue(); >> > > if (ee) >> > > remove(ee); >> > > else >> > > break; >> > > } >> > > >> > >> > It seems that the code I read had been changed on this section you >> showed >> > above, as my coworker have optimized it a bit. But thanks for your >> > explanation all the same. >> > >> > >> > > >> > > >> > > >> > > On Sat, Dec 29, 2012 at 9:39 AM, Yunkai Zhang <yunkai...@gmail.com> >> > wrote: >> > > >> > > > Hi folks: >> > > > >> > > > I'm reading code about RamCacheLRU, but I was confused by >> > > RamCacheLRU->lru >> > > > queue defined as following: >> > > > >> > > > struct RamCacheLRU: public RamCache { >> > > > ... >> > > > Que(RamCacheLRUEntry, lru_link) lru; >> > > > DList(RamCacheLRUEntry, hash_link) *bucket; >> > > > ... >> > > > }; >> > > > >> > > > By reading put/get/remove functions of RamCacheLRU class, it seems >> > that >> > > > LRU algorithm was implemented by accessing *bucket* list instead of >> > *lru* >> > > > queue. >> > > > >> > > > Do I understand it correctly? if so, we can remove lru queue and >> > relative >> > > > code to speed up the put/get function of LRU a bit. >> > > > >> > > > -- >> > > > Yunkai Zhang >> > > > Work at Taobao >> > > > >> > > >> > >> > >> > >> > -- >> > Yunkai Zhang >> > Work at Taobao >> > >> > > > > -- > Yunkai Zhang > Work at Taobao > -- Yunkai Zhang Work at Taobao
