From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <463B004D.6060402@yahoo.com.au> Date: Fri, 04 May 2007 19:43:41 +1000 From: Nick Piggin MIME-Version: 1.0 Subject: Re: 2.6.22 -mm merge plans -- vm bugfixes References: <20070430162007.ad46e153.akpm@linux-foundation.org> <4636FDD7.9080401@yahoo.com.au> <4638009E.3070408@yahoo.com.au> <46393BA7.6030106@yahoo.com.au> <20070503103756.GA19958@infradead.org> <4639DBEC.2020401@yahoo.com.au> <463AFB8C.2000909@yahoo.com.au> In-Reply-To: <463AFB8C.2000909@yahoo.com.au> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: Cc: Christoph Hellwig , Hugh Dickins , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrea Arcangeli , Benjamin Herrenschmidt List-ID: Nick Piggin wrote: > Nick Piggin wrote: > >> Christoph Hellwig wrote: > > >>> Is that every fork/exec or just under certain cicumstances? >>> A 5% regression on every fork/exec is not acceptable. >> >> >> >> Well after patch2, G5 fork is 3% and exec is 1%, I'd say the P4 >> numbers will be improved as well with that patch. Then if we have >> specific lock/unlock bitops, I hope it should reduce that further. > > > OK, with the races and missing barriers fixed from the previous patch, > plus the attached one added (+patch3), numbers are better again (I'm not > sure if I have the ppc barriers correct though). > > These ops could also be put to use in bit spinlocks, buffer lock, and > probably a few other places too. > > 2.6.21 1.49-1.51 164.6-170.8 741.8-760.3 > +patch 1.71-1.73 175.2-180.8 780.5-794.2 > +patch2 1.61-1.63 169.8-175.0 748.6-757.0 > +patch3 1.54-1.57 165.6-170.9 748.5-757.5 > > So fault performance goes to under 5%, fork is in the noise, exec is > still up 1%, but maybe that's noise or cache effects again. OK, with my new lock/unlock_page, dd if=large (bigger than RAM) sparse file of=/dev/null with an experimentally optimal block size (32K) goes from 626MB/s to 683MB/s on 2 CPU G5 booted with maxcpus=1. -- SUSE Labs, Novell Inc. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org