From mboxrd@z Thu Jan 1 00:00:00 1970 From: Khalid Aziz Subject: Re: [PATCH v3] sched/fair: Add advisory flag for borrowing a timeslice Date: Tue, 25 Nov 2014 12:23:10 -0700 Message-ID: <5474D71E.8070603@oracle.com> References: <1416862595-24513-1-git-send-email-khalid.aziz@oracle.com> <54749617.5030309@oracle.com> <1416940024.26209.2.camel@linux-t7sj.site> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1416940024.26209.2.camel@linux-t7sj.site> Sender: linux-doc-owner@vger.kernel.org To: Davidlohr Bueso Cc: Thomas Gleixner , corbet@lwn.net, mingo@redhat.com, hpa@zytor.com, peterz@infradead.org, riel@redhat.com, akpm@linux-foundation.org, rientjes@google.com, ak@linux.intel.com, mgorman@suse.de, raistlin@linux.it, kirill.shutemov@linux.intel.com, atomlin@redhat.com, avagin@openvz.org, gorcunov@openvz.org, serge.hallyn@canonical.com, athorlton@sgi.com, oleg@redhat.com, vdavydov@parallels.com, daeseok.youn@gmail.com, keescook@chromium.org, yangds.fnst@cn.fujitsu.com, sbauer@eng.utah.edu, vishnu.ps@samsung.com, axboe@fb.com, paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-api@vger.kernel.org List-Id: linux-api@vger.kernel.org On 11/25/2014 11:27 AM, Davidlohr Bueso wrote: > On Tue, 2014-11-25 at 07:45 -0700, Khalid Aziz wrote: >> This solution has been used by both database and java on other OSs and >> has shown performance improvement. Andrew had asked for performance >> numbers on Linux with this patch last time I sent this out and it took >> me a while to get performance folks to run a full TPC-C workload. They >> did see a 3% improvement in tpcc as I noted in commit log and that is a >> significant improvement. > > 3% for such a change seems pretty worthless... I would have expected > this having to impact performance much more. > Performance impact will depend upon how big a bottleneck the spinlock was creating and how severe the resulting convoy problem was. Database guys try to squeeze every bit out of the system and 3% is considered to be very good gain. 10% gain would have been nicer :) -- Khalid