Re: using jemalloc in trusty

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>>To me it looks like the libbrary is being used, but please advise if it is otherwise.

can you do a "perf top", to see if malloc are done through tcmalloc or jemalloc ?


----- Mail original -----
De: "Andrei Mikhailovsky" <andrei@xxxxxxxxxx>
À: "Joshua M. Boniface" <joshua@xxxxxxxxxxx>
Cc: "ceph-users" <ceph-users@xxxxxxxxxxxxxx>
Envoyé: Mercredi 25 Mai 2016 12:39:10
Objet: Re:  using jemalloc in trusty

Interesting, 

I've switched to jemalloc about a month ago while running Hammer. after installing the library and using the /etc/ld.so.preload I am seeing that all ceph-osd processes are indeed using the library. I've upgraded to Jewel a few days ago and see the same picture: 

# time lsof |grep ceph-osd |grep jemalloc 
ceph-osd 1991 ceph mem REG 8,129 207488 525275 /usr/lib/x86_64-linux-gnu/libjemalloc.so.1 
ceph-osd 1991 2094 ceph mem REG 8,129 207488 525275 /usr/lib/x86_64-linux-gnu/libjemalloc.so.1 
ceph-osd 1991 6689 ceph mem REG 8,129 207488 525275 /usr/lib/x86_64-linux-gnu/libjemalloc.so.1 
ceph-osd 2341 ceph mem REG 8,129 207488 525275 /usr/lib/x86_64-linux-gnu/libjemalloc.so.1 
ceph-osd 2341 2414 ceph mem REG 8,129 207488 525275 /usr/lib/x86_64-linux-gnu/libjemalloc.so.1 
ceph-osd 2341 3813 ceph mem REG 8,129 207488 525275 /usr/lib/x86_64-linux-gnu/libjemalloc.so.1 

I've not done anything else apart from apt-get install <library-package> and added it to the ld.so.preload. 

I've also ran a few dd tests from about 20 vms before and after switching the library and see a significant performance increase for parallel writes. The increase was around 5x, which I couldn't believe at first, but repeated tests verified that. 

To me it looks like the libbrary is being used, but please advise if it is otherwise. 

Thanks 

Andrei 


----- Original Message ----- 
> From: "Joshua M. Boniface" <joshua@xxxxxxxxxxx> 
> To: "ceph-users" <ceph-users@xxxxxxxxxxxxxx> 
> Sent: Tuesday, 24 May, 2016 19:00:55 
> Subject: Re:  using jemalloc in trusty 

> Hello list: 
> 
> I've been building my own Ceph Debian Jessie packages (and QEMU too) to get 
> jemalloc support, and in Infernalis I was explicitly setting a dependency in 
> the control file which seemed to work. However, that option is gone in Jewel, 
> replaced with this /etc/default/ceph preload. Without any code changes from 
> default, and enabling the jemalloc line in that file, I'm seeing both libraries 
> in use by every daemon, e.g.: 
> 
>> ms_pipe_r 8659 31756 ceph mem REG 253,0 640600 
>> 21056 /usr/lib/libtcmalloc.so.4.2.2 
>> ms_pipe_r 8659 31756 ceph mem REG 253,0 223936 
>> 6829 /usr/lib/x86_64-linux-gnu/libjemalloc.so.1 
>> ms_pipe_w 8659 31757 ceph mem REG 253,0 640600 
>> 21056 /usr/lib/libtcmalloc.so.4.2.2 
>> ms_pipe_w 8659 31757 ceph mem REG 253,0 223936 
>> 6829 /usr/lib/x86_64-linux-gnu/libjemalloc.so.1 
> 
> Given the messages in this thread, it seems that the jemalloc library isn't 
> actually being used? But if so, why would it be loaded (and why would tcmalloc 
> *also* be loaded)? And if we still need to add explicit support, does anyone 
> have any advice for how to achieve this? 
> 
> My build procedure is quite simply: 
> 
> $ git clone https://github.com/ceph/ceph.git && cd ceph 
> $ sudo dpkg-buildpackage -us -uc -j8 
> 
> Followed by adding the generated packages to my local repo and standard "apt-get 
> install". And yes, the main Ceph packages have dependencies on "libtcmalloc-*" 
> (just tested trying to remove them). 
> 
> -- 
> Joshua M. Boniface 
> Linux System Ærchitect 
> Sigmentation fault. Core dumped. 
> 
> On 24/05/16 01:49 PM, Alexandre DERUMIER wrote: 
>>>> Is it true for Xenial too or only for Trusty? I don't want to rebuild Jewel on 
>>>> xenial hosts... 
>> yes, for xenial (and debian wheezy/jessie too). 
>> 
>> I don't don't why they are LD_PRELOAD commented in /etc/default/ceph, 
>> because it's really don't do nothing, if tcmalloc is present. 
>> 
>> you could try to remove tcmalloc packages (libgoogle-perftools4), 
>> 
>> but I think that ceph packages have dependencies on it .... 
>> 
>> 
>> 
>> ----- Mail original ----- 
>> De: "Max A. Krasilnikov" <pseudo@xxxxxxxxxxxx> 
>> Cc: "ceph-users" <ceph-users@xxxxxxxxxxxxxx> 
>> Envoyé: Mardi 24 Mai 2016 19:33:48 
>> Objet: Re:  using jemalloc in trusty 
>> 
>> Hello! 
>> 
>> On Mon, May 23, 2016 at 02:34:37PM +0000, Somnath.Roy wrote: 
>> 
>>> You need to build ceph code base to use jemalloc for OSDs..LD_PRELOAD won't 
>>> work.. 
>> Is it true for Xenial too or only for Trusty? I don't want to rebuild Jewel on 
>> xenial hosts... 
>> 
> 
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