Hi Sommath,

is it only on osds ?

or also clients ?

What is the tmalloc version on ubuntu ? (I would like to known if the problem 
exist also on debian)

Regards,

Alexandre
----- Mail original -----
De: "Somnath Roy" <[email protected]>
À: "ceph-devel" <[email protected]>
Envoyé: Vendredi 27 Mars 2015 00:18:57
Objet: tcmalloc issue

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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