From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: Re: strange guest slowness after some time Date: Tue, 26 May 2009 13:49:57 +0200 Message-ID: <4A1BD765.4080405@wpkg.org> References: <49B29705.6000904@wpkg.org> <49D30801.5020201@wpkg.org> <49DA1D75.6000604@wpkg.org> <200904081019.14768.rusty@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "David S. Ahern" , Felix Leimbach , avi@redhat.com, kvm@vger.kernel.org, Anthony Liguori To: Rusty Russell Return-path: Received: from mx03.syneticon.net ([78.111.66.105]:47111 "EHLO mx03.syneticon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753153AbZEZLtn (ORCPT ); Tue, 26 May 2009 07:49:43 -0400 In-Reply-To: <200904081019.14768.rusty@rustcorp.com.au> Sender: kvm-owner@vger.kernel.org List-ID: Rusty Russell wrote: > On Tuesday 07 April 2009 00:49:17 Tomasz Chmielewski wrote: >> Tomasz Chmielewski schrieb: >> >>> As I mentioned, it was using virtio net. >>> >>> Guests running with e1000 (and virtio_blk) don't have this problem. >> Also, virtio_console seem to be affected by this "slowness" issue. > > I'm pretty sure this is different. Older virtio_console code ignored > interrupts and polled, and use a heuristic to back off on polling (this was > because we used the generic "hvc" infrastructure which hacked support). > > You'll find a delay on the first keystroke after idle, but none on the > second. I still observe this "slowness" with kvm-86 after the guest is running for some time (virtio_net and virtio_console seem to be affected; guest restart doesn't fix it). -- Tomasz Chmielewski http://wpkg.org