From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: Poor DBT-3 pgsql 8way numbers on recent 2.6 mm kernels From: Ram Pai In-Reply-To: <1079369109.2961.181.camel@localhost> References: <1079130684.2961.134.camel@localhost> <20040312233900.0d68711e.akpm@osdl.org> <405379ED.A7D6B1E4@us.ibm.com> <20040313134842.78695cc6.akpm@osdl.org> <1079369109.2961.181.camel@localhost> Content-Type: text/plain Message-Id: <1079379197.2844.32.camel@dyn319094bld.beaverton.ibm.com> Mime-Version: 1.0 Date: 15 Mar 2004 11:33:17 -0800 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: maryedie@osdl.org Cc: Andrew Morton , Badari Pulavarty , linux-mm@kvack.org List-ID: On Mon, 2004-03-15 at 08:45, Mary Edie Meredith wrote: > > > > And if that is indeed the case I'd be suspecting the CPU scheduler. But > > then, Meredith's profiles show almost completely idle CPUs. > > > > The simplest way to hunt this down is the old binary-search-through-the-patches process. But that requires some test which takes just a few minutes. > > If you are referring to a binary search to find when the > performance changed, I can do this with STP. It may take > some time, but I'm willing. I didnt want to do that if > the problem was a known problem. Based on your data, I dont think readahead patch is responsible. However since you are seeing this only on mm kernel there is a small needle of suspicion on the readahead patch. How about reverting only the readahaed patch in mm tree and trying it out? http://www.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.3-rc1/2.6.3-rc1-mm1/broken-out/adaptive-lazy-readahead.patch My DSS workload benchmarks always touches the disk because I have only 4GB memory configured. I will give a try with 8GB memory and see if I see any of your behavior. (I wont be able to put all my database in memory)... RP > -- > 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: aart@kvack.org > -- 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: aart@kvack.org