From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Tomas Subject: Re: Re: [RFC] ext3 writepages for writeback mode Date: Mon, 14 Feb 2005 19:34:24 +0300 Message-ID: References: <1108085493.20053.1191.camel@dyn318077bld.beaverton.ibm.com> <20050210175327.7b4a508b.akpm@osdl.org> <1108164542.20053.1232.camel@dyn318077bld.beaverton.ibm.com> <20050211155858.354520bb.akpm@osdl.org> <1108169488.20053.1241.camel@dyn318077bld.beaverton.ibm.com> <420E9098.9000903@us.ibm.com> <1108396701.20053.1248.camel@dyn318077bld.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Alex Tomas , Andrew Morton , ext2-devel , linux-fsdevel@vger.kernel.org, sct@redhat.com To: Badari Pulavarty In-Reply-To: <1108396701.20053.1248.camel@dyn318077bld.beaverton.ibm.com> (Badari Pulavarty's message of "14 Feb 2005 07:58:22 -0800") Sender: ext2-devel-admin@lists.sourceforge.net Errors-To: ext2-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: List-Id: linux-fsdevel.vger.kernel.org >>>>> Badari Pulavarty (BP) writes: BP> Sure. I think it will improve the allocation case. BP> Non-allocation case, should be pretty much same, provided BP> I got contiguous layout on the disk. Isn't it ? not allocation only: [root@bob root]# time /work/tests/fwrite /test/fff 64 10000 real 0m13.102s user 0m0.027s sys 0m4.003s [root@bob root]# time /work/tests/fwrite /test/fff 64 10000 real 0m22.210s user 0m0.006s sys 0m3.241s [root@bob root]# time /work/tests/fwrite /test/fff 64 10000 real 0m23.242s user 0m0.005s sys 0m3.202s [root@bob root]# time /work/tests/fwrite /test/fff 64 10000 real 0m24.777s user 0m0.011s sys 0m3.175s I think at least couple things're involved: - for already allocated block I don't open a transaction - extents code caches last found extent, so most lookups just do few compares with in-inode integers and don't walk though a tree btw, I've observed the following issue: sometimes vm can run several ->writepages() against a same file or mix ->writepages() with ->writepage(). I think this can break layout ... thanks, Alex ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click