On 15. juni. 2009, at 10.48, JC wrote:
Hi,
just out of curiosity, what are those tracks?
I was thinking as Jaime per slab class mutex
This mutex shouldn't really be such a big problem, because it is only
used when you try to insert / modify something in your cache... (well,
of course this depends on your use pattern, but are you really doing
that high number of concurrent incr/decr/append/prepend/set/add/
replace ?)
and also static division
of the hashtable with specific mutex for each part; am I in the right
direction?
I have a version of memcached where I partitioned the hash into n
partitions and use a mutex per partition. I have not pushed that
version to github yet, because I haven't finished up benchmarking and
running lock analysis on it....
Cheers,
Trond
cheers,
Jean-Charles
On Jun 15, 9:11 am, Toru Maesaka <tmaes...@gmail.com> wrote:
Hi!
Apologies for the late reply.
Things you've mentioned are correct and we've talked about
SMP performance issues of the daemon for a while at hackathons,
events, IRC and etc. As Dustin had mentioned, some experimental
work has been done and hopefully things will look better in future
releases :)
You know, things were worse prior to 1.4 with the global stats lock
so we've actually come quite far since 1.2 ;)
Cheers,
Toru
On Sat, Jun 13, 2009 at 2:32 AM, Jaime
Medrano<jaime.medr...@gmail.com> wrote:
I have been doing a little lock profiling on memcached and I have
found that cache_lock has a lot of contention in machines with more
than 4 processors.
Mutex contention is very bad when using libevent because it means
that
all connections assigned to the thread that is waiting are frozen.
Is there any plan on improving that?
I think that instead of using a global mutex, locking could be
done on
a per bucket basis plus an additional lock for LRU list management.
Would you be interested on any work on that direction?
Regards,
Jaime.
--
Trond Norbye
Web Scale Infrastructure E-mail: trond.nor...@sun.com
SUN Microsystems Phone: +47 73842100
Haakon VII's gt. 7B Fax: +47 73842101
7485 Trondheim, Norway
