FWIW, I've seen perf top traces like this in the past. It's making me
wonder how many times I've seen this and not connected the dots.
Mark
On 03/26/2015 06:18 PM, Somnath Roy wrote:
Sage,
Here is the tcmalloc issue I was talking in the performance meeting.
http://code.google.com/p/gperftools/issues/detail?id=585
The tcmalloc is consuming lot of cpus (and eventually slowing down the performance) with the following perf top trace.
25.73% libtcmalloc.so.4.1.2 [.] tcmalloc::CentralFreeList::FetchFromSpans()
12.52% libtcmalloc.so.4.1.2 [.] tcmalloc::ThreadCache::ReleaseToCentralCache(tcmalloc::ThreadCache::FreeList*, unsigned long, int)
11.62% libtcmalloc.so.4.1.2 [.] tcmalloc::CentralFreeList::ReleaseToSpans(void*)
1.56% [kernel] [k] __copy_user_nocache
1.44% libtcmalloc.so.4.1.2 [.] tcmalloc::CentralFreeList::RemoveRange(void*, void*, int)
1.39% libtcmalloc.so.4.1.2 [.] tcmalloc::CentralFreeList::ReleaseListToSpans(void*)
0.89% libtcmalloc.so.4.1.2 [.] operator new(unsigned long)
The TCMALLOC_MAX_TOTAL_THREAD_CACHE_BYTES is alleviating that but the env variable setting for this is a noop in the binary we are having in Ubuntu 14.04. It is fixed in gperftools-2.1.90 release.
See the following link.
http://code.google.com/p/gperftools/
We can request Ubuntu guys to incorporate this version or the latest tcmalloc version which is gperftools-2.4.
It will be really helpful if you can push them to incorporate this in 14.04 updates.
Thanks & Regards
Somnath
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