From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH] fs: pipe/sockets/anon dentries should not have a parent Date: Fri, 21 Nov 2008 16:28:29 +0100 Message-ID: <4926D39D.9050603@cosmosbay.com> References: <20081121083044.GL16242@elte.hu> <49267694.1030506@cosmosbay.com> <20081121.010508.40225532.davem@davemloft.net> <4926AEDB.10007@cosmosbay.com> <4926D022.5060008@cosmosbay.com> <20081121152148.GA20388@elte.hu> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20081121152148.GA20388-X9Un+BFzKDI@public.gmane.org> Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="iso-8859-1"; format="flowed" To: Ingo Molnar Cc: David Miller , cl-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, rjw-KKrjLPT3xs0@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, efault-Mmb7MZpHnFY@public.gmane.org, a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org, Linux Netdev List Ingo Molnar a =E9crit : > * Eric Dumazet wrote: >=20 >> Before patch, time to run 8 millions of close(socket()) calls on 8=20 >> CPUS was : >> >> real 0m27.496s >> user 0m0.657s >> sys 3m39.092s >> >> After patch : >> >> real 0m23.997s >> user 0m0.682s >> sys 3m11.193s >=20 > cool :-) >=20 > What would it take to get it down to: >=20 >>> Cost if run one one cpu : >>> >>> real 0m1.561s >>> user 0m0.092s >>> sys 0m1.469s >=20 > i guess asking for a wall-clock cost of 1.561/8 would be too much? :) >=20 It might be possible, depending on the level of hackery I am allowed to= inject in fs/dcache.c and fs/inode.c :) wall cost of 1.56 (each cpu runs one loop of one million iterations)