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.
>
> 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
