From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 0/4] Rework alarm timer infrastrucure - take2 Date: Wed, 22 Aug 2007 19:45:00 +0300 Message-ID: <46CC680C.1030307@qumranet.com> References: <20070817231149.544849769@gmail.com> <20070818220252.GA19526@dreamland.darkstar.lan> <68676e00708190952g7d4751c2g87a6ff71dd278f71@mail.gmail.com> <46C89A8E.7040609@qumranet.com> <20070820212058.GA6713@dreamland.darkstar.lan> <46CAD607.2080504@qumranet.com> <20070821193834.GB13544@dreamland.darkstar.lan> <46CBC34F.6060601@qumranet.com> <20070822161211.GA30147@dreamland.darkstar.lan> <46CC6285.3090904@qumranet.com> <68676e00708220938y57c07edas705fc8360aefcb78@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Dan Kenigsberg , kvm-devel-TtF/mJH4Jtrk1uMJSBkQmQ@public.gmane.org, qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org To: Luca Return-path: In-Reply-To: <68676e00708220938y57c07edas705fc8360aefcb78-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Luca wrote: >>> This is QEMU, with dynticks and HPET: >>> >>> % time seconds usecs/call calls errors syscall >>> ------ ----------- ----------- --------- --------- ---------------- >>> 52.10 0.002966 0 96840 clock_gettime >>> 19.50 0.001110 0 37050 timer_gettime >>> 10.66 0.000607 0 20086 timer_settime >>> 10.40 0.000592 0 8985 2539 sigreturn >>> 4.94 0.000281 0 8361 2485 select >>> 2.41 0.000137 0 8362 gettimeofday >>> ------ ----------- ----------- --------- --------- ---------------- >>> 100.00 0.005693 179684 5024 total >>> >>> >> This looks like 250 Hz? >> > > Nope: > > # CONFIG_NO_HZ is not set > # CONFIG_HZ_100 is not set > # CONFIG_HZ_250 is not set > # CONFIG_HZ_300 is not set > CONFIG_HZ_1000=y > CONFIG_HZ=1000 > > and I'm reading it from /proc/config.gz on the guest. > Yeah, thought so -- so dyntick is broken at present. Or maybe your host kernel can't support such a high rate. Probably needs hrtimers or qemu dyntick over hpet oneshot support. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/