Thanks Chaitanya ** Description changed:
+ [Impact] + When under memory pressure, tcmalloc will consume increasing amounts of CPU cycles resulting in performance degradation; the mechanism to permit a larger thread cache is broken, so the pinch point can be worked around by increasing the amount of memory to relieve this pressure. + + [Test Case] + (compile attached binary) + g++ -o gperftest gperftest.c -ltcmalloc + export TCMALLOC_MAX_TOTAL_THREAD_CACHE_BYTES=67108864 + ./gperftest + Tcmalloc BUG! TCMALLOC_MAX_TOTAL_THREAD_CACHE_BYTES: 67108864 Internal Size: 33554432 different + + [Regression Potential] + Fix committed upstream and isolate to a specific code path. + + [Original Bug Report] + Reported by upstream: > 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 ** Summary changed: - tcmalloc performance degredation over time + [SRU] tcmalloc performance degredation over time -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to google-perftools in Ubuntu. https://bugs.launchpad.net/bugs/1439277 Title: [SRU] tcmalloc performance degredation over time To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/google-perftools/+bug/1439277/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
