From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Date: Sun, 18 Sep 2005 10:56:31 +0000 Subject: Re: Volanomark regress on ia64 Message-Id: <432D47DF.30706@yahoo.com.au> List-Id: References: <200509160040.j8G0eFg06734@unix-os.sc.intel.com> In-Reply-To: <200509160040.j8G0eFg06734@unix-os.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Chen, Kenneth W wrote: > Take a look at http://kernel-perf.sourceforge.net/results.machine_id&.html > > First chart with volanomark benchmark. It took ~ 11% performance regression > on 2.6.13-git9 and 2.6.14-rc1. > > It is not those two particular kernel version have the problem per se. It > would've shown on 2.6.13-rc1 when default hz rate was switched to 250. Last > week, I happened to audit the system and made the hz switch and the problem > showed up. > > Hz00 cpu idle is about 54%, the raw throughput is 74935 msgs/sec > Hz%0 cpu idle is about 58%, the raw throughput is 67246 msgs/sec > > I think it has something to do with the scheduler load balance. While I'm > looking into schedstat and etc. Posting here for everyone to pour over the > issue. > > vmstat/readprofle/schedstat result with 1K hz and 250 hz attached. > Hi Ken, Made any progress yet? It looks like the problem is confined to ia64? Are the x86-64 machines also running with HZ set to 250? I would look at differences between SD_CPU_INIT for ia64 versus the generic definition. cache_hot_time and cache_nice_tries by the looks, both those could cause increased idle time. Nick -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com