From fuse-devel Wed Jun 20 10:09:52 2012 From: Stefan Westerfeld Date: Wed, 20 Jun 2012 10:09:52 +0000 To: fuse-devel Subject: Re: [fuse-devel] fuse stat performance on multicore systems Message-Id: <20120620100952.GB7140 () space ! twc ! de> X-MARC-Message: https://marc.info/?l=fuse-devel&m=134018734403546 Hi! On Wed, Jun 13, 2012 at 12:21:09PM -0300, Han-Wen Nienhuys wrote: > On Wed, Jun 13, 2012 at 11:52 AM, Stefan Westerfeld wrote: > > > So it seems that FuSE becomes really slow for stat/readdir when more than > > one CPU is available (probably because the userspace client and filesystem > > work ends up being done on different CPUs). > > You should probably verify this theory first? You can instrument the > library to measure how much time it spends to answer stat calls. Ok, I'll try to gather more data by instrumenting libfuse. I'll be on vacation for three weeks now, and won't have access to a multicore machine there. So I will collect more data when I'm back, and mail it to the list. > FUSE creates a thread per request, reusing threads if possible. > Another possible slowdown is that the FUSE threads run on different > CPUs and contend for shared locks to inspect the in-process inode > tree. I don't believe that can be the cause, because if there is a single userspace process that does stat/readdir calls, then only one FuSE thread should be active, as there is at most one open FuSE request to process at any given time. Cu... Stefan -- Stefan Westerfeld, Hamburg/Germany, http://space.twc.de/~stefan ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ fuse-devel mailing list fuse-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/fuse-devel