From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49587) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V9Fg6-00078e-MT for qemu-devel@nongnu.org; Tue, 13 Aug 2013 10:34:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V9Ffz-0005JA-7J for qemu-devel@nongnu.org; Tue, 13 Aug 2013 10:34:30 -0400 Received: from thoth.sbs.de ([192.35.17.2]:34119) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V9Ffy-0005Ip-Tp for qemu-devel@nongnu.org; Tue, 13 Aug 2013 10:34:23 -0400 Message-ID: <520A43E3.9080804@siemens.com> Date: Tue, 13 Aug 2013 16:34:11 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <1376239405-4084-1-git-send-email-alex@alex.org.uk> <520A2511.4000709@siemens.com> <307AE3B5-FAFE-4E9C-A336-092245809528@alex.org.uk> <520A33B4.9030207@siemens.com> <14A27B81-C9FD-4EE5-BC4A-7106CD70527A@alex.org.uk> <520A3888.9020307@siemens.com> <20130813142204.GA3008@stefanha-thinkpad.redhat.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC] [PATCHv10 00/31] aio / timers: Add AioContext timers and use ppoll List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Bligh Cc: Kevin Wolf , Anthony Liguori , Stefan Hajnoczi , qemu-devel@nongnu.org, liu ping fan , Stefan Hajnoczi , Paolo Bonzini , MORITA Kazutaka , rth@twiddle.net On 2013-08-13 16:26, Alex Bligh wrote: > > On 13 Aug 2013, at 15:22, Stefan Hajnoczi wrote: > >> We can change the semantics of aio_poll() so long as we don't break >> existing callers and tests. It would make sense to do that after >> merging the io_flush and AioContext timers series. > > Whilst I think we should wait until your 'drop ioflush' stuff > is merged, without doing an audit, I doubt there is any > existing code which uses an AioContext with just its > notifier fd, and is calls aio_poll with blocking=1. If there is, > I doubt that code does anything useful :-) It would be great to have a use case for this upstream, maybe one that is less special than mine. Ping Fan was talking about that he's working on the HPET. Decoupling it from our lousy iothread should improve its timer accuracy noticeably, maybe finally making it usable for Windows guest. On the other side, it's far from easy to disentangle its logic from the rest of a PC platform devices. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux