From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yoshihiro YUNOMAE Subject: Re: Re: Re: [RFC PATCH 0/6] virtio-trace: Support virtio-trace Date: Tue, 31 Jul 2012 09:52:30 +0900 Message-ID: <50172C4E.7090202@hitachi.com> References: <20120724023657.6600.52706.stgit@ltc189.sdl.hitachi.co.jp> <20120726113537.GH9473@amit.redhat.com> <5012576F.7040500@hitachi.com> <20120727094320.GK18651@amit.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120727094320.GK18651@amit.redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Amit Shah Cc: Arnd Bergmann , Greg Kroah-Hartman , Frederic Weisbecker , qemu-devel@nongnu.org, Borislav Petkov , linux-kernel@vger.kernel.org, Herbert Xu , "Franch Ch. Eigler" , Ingo Molnar , Mathieu Desnoyers , Steven Rostedt , Anthony Liguori , yrl.pp-manager.tt@hitachi.com, Masami Hiramatsu , virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org Hi Amit, Sorry for the late reply. (2012/07/27 18:43), Amit Shah wrote: > On (Fri) 27 Jul 2012 [17:55:11], Yoshihiro YUNOMAE wrote: >> Hi Amit, >> >> Thank you for commenting on our work. >> >> (2012/07/26 20:35), Amit Shah wrote: >>> On (Tue) 24 Jul 2012 [11:36:57], Yoshihiro YUNOMAE wrote: >> [...] >>>> >>>> ***Just enhancement ideas*** >>>> - Support for trace-cmd >>>> - Support for 9pfs protocol >>>> - Support for non-blocking mode in QEMU >>> >>> There were patches long back (by me) to make chardevs non-blocking but >>> they didn't make it upstream. Fedora carries them, if you want to try >>> out. Though we want to converge on a reasonable solution that's >>> acceptable upstream as well. Just that no one's working on it >>> currently. Any help here will be appreciated. >> >> Thanks! In this case, since a guest will stop to run when host reads >> trace data of the guest, char device is needed to add a non-blocking >> mode. I'll read your patch series. Is the latest version 8? >> http://lists.gnu.org/archive/html/qemu-devel/2010-12/msg00035.html > > I suppose the latest version on-list is what you quote above. The > objections to the patch series are mentioned in Anthony's mails. I'll check the mails. > Hans maintains a rebased version of the patches in his tree at > > http://cgit.freedesktop.org/~jwrdegoede/qemu/ > > those patches are included in Fedora's qemu-kvm, so you can try that > out if it improves performance for you. Thanks. I'll check those patches. >>>> - Make "vhost-serial" >>> >>> I need to understand a) why it's perf-critical, and b) why should the >>> host be involved at all, to comment on these. >> >> a) To make collecting overhead decrease for application on a guest. >> (see above) >> b) Trace data of host kernel is not involved even if we introduce this >> patch set. > > I see, so you suggested vhost-serial only because you saw the guest > stopping problem due to the absence of non-blocking code? If so, it > now makes sense. I don't think we need vhost-serial in any way yet. I understood. We suggested vhost-serial as one of the ideas for improving performances. Other features(trace-cmd, 9pfs, and non-blocking chardev) should be supported first, I think. > BTW where do you parse the trace data obtained from guests? On a > remote host? It is the best that we can parse the data on a remote host in this tracing system. Existing trace-cmd can already parse it on a remote site. If we add the feature collecting event-format data(guest's debugfs has that) from guests, we can parse tracing data on a remote host as well as on a host running guests. Thank you, -- Yoshihiro YUNOMAE Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: yoshihiro.yunomae.ez@hitachi.com From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754229Ab2GaAwh (ORCPT ); Mon, 30 Jul 2012 20:52:37 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:46994 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753725Ab2GaAwf (ORCPT ); Mon, 30 Jul 2012 20:52:35 -0400 X-AuditID: b753bd60-a0885ba000000655-a3-50172c4f4ca5 X-AuditID: b753bd60-a0885ba000000655-a3-50172c4f4ca5 Message-ID: <50172C4E.7090202@hitachi.com> Date: Tue, 31 Jul 2012 09:52:30 +0900 From: Yoshihiro YUNOMAE User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:13.0) Gecko/20120604 Thunderbird/13.0 MIME-Version: 1.0 To: Amit Shah Cc: linux-kernel@vger.kernel.org, Herbert Xu , Arnd Bergmann , Frederic Weisbecker , yrl.pp-manager.tt@hitachi.com, qemu-devel@nongnu.org, Borislav Petkov , virtualization@lists.linux-foundation.org, "Franch Ch. Eigler" , Ingo Molnar , Mathieu Desnoyers , Steven Rostedt , Anthony Liguori , Greg Kroah-Hartman , Masami Hiramatsu Subject: Re: Re: Re: [RFC PATCH 0/6] virtio-trace: Support virtio-trace References: <20120724023657.6600.52706.stgit@ltc189.sdl.hitachi.co.jp> <20120726113537.GH9473@amit.redhat.com> <5012576F.7040500@hitachi.com> <20120727094320.GK18651@amit.redhat.com> In-Reply-To: <20120727094320.GK18651@amit.redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Amit, Sorry for the late reply. (2012/07/27 18:43), Amit Shah wrote: > On (Fri) 27 Jul 2012 [17:55:11], Yoshihiro YUNOMAE wrote: >> Hi Amit, >> >> Thank you for commenting on our work. >> >> (2012/07/26 20:35), Amit Shah wrote: >>> On (Tue) 24 Jul 2012 [11:36:57], Yoshihiro YUNOMAE wrote: >> [...] >>>> >>>> ***Just enhancement ideas*** >>>> - Support for trace-cmd >>>> - Support for 9pfs protocol >>>> - Support for non-blocking mode in QEMU >>> >>> There were patches long back (by me) to make chardevs non-blocking but >>> they didn't make it upstream. Fedora carries them, if you want to try >>> out. Though we want to converge on a reasonable solution that's >>> acceptable upstream as well. Just that no one's working on it >>> currently. Any help here will be appreciated. >> >> Thanks! In this case, since a guest will stop to run when host reads >> trace data of the guest, char device is needed to add a non-blocking >> mode. I'll read your patch series. Is the latest version 8? >> http://lists.gnu.org/archive/html/qemu-devel/2010-12/msg00035.html > > I suppose the latest version on-list is what you quote above. The > objections to the patch series are mentioned in Anthony's mails. I'll check the mails. > Hans maintains a rebased version of the patches in his tree at > > http://cgit.freedesktop.org/~jwrdegoede/qemu/ > > those patches are included in Fedora's qemu-kvm, so you can try that > out if it improves performance for you. Thanks. I'll check those patches. >>>> - Make "vhost-serial" >>> >>> I need to understand a) why it's perf-critical, and b) why should the >>> host be involved at all, to comment on these. >> >> a) To make collecting overhead decrease for application on a guest. >> (see above) >> b) Trace data of host kernel is not involved even if we introduce this >> patch set. > > I see, so you suggested vhost-serial only because you saw the guest > stopping problem due to the absence of non-blocking code? If so, it > now makes sense. I don't think we need vhost-serial in any way yet. I understood. We suggested vhost-serial as one of the ideas for improving performances. Other features(trace-cmd, 9pfs, and non-blocking chardev) should be supported first, I think. > BTW where do you parse the trace data obtained from guests? On a > remote host? It is the best that we can parse the data on a remote host in this tracing system. Existing trace-cmd can already parse it on a remote site. If we add the feature collecting event-format data(guest's debugfs has that) from guests, we can parse tracing data on a remote host as well as on a host running guests. Thank you, -- Yoshihiro YUNOMAE Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: yoshihiro.yunomae.ez@hitachi.com From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:39016) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sw0hU-0003GI-TJ for qemu-devel@nongnu.org; Mon, 30 Jul 2012 20:52:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Sw0hT-0003Bh-Dd for qemu-devel@nongnu.org; Mon, 30 Jul 2012 20:52:40 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:46996) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sw0hS-0003Ao-Uq for qemu-devel@nongnu.org; Mon, 30 Jul 2012 20:52:39 -0400 Message-ID: <50172C4E.7090202@hitachi.com> Date: Tue, 31 Jul 2012 09:52:30 +0900 From: Yoshihiro YUNOMAE MIME-Version: 1.0 References: <20120724023657.6600.52706.stgit@ltc189.sdl.hitachi.co.jp> <20120726113537.GH9473@amit.redhat.com> <5012576F.7040500@hitachi.com> <20120727094320.GK18651@amit.redhat.com> In-Reply-To: <20120727094320.GK18651@amit.redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH 0/6] virtio-trace: Support virtio-trace List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Amit Shah Cc: Arnd Bergmann , Greg Kroah-Hartman , Frederic Weisbecker , qemu-devel@nongnu.org, Borislav Petkov , linux-kernel@vger.kernel.org, Herbert Xu , "Franch Ch. Eigler" , Ingo Molnar , Mathieu Desnoyers , Steven Rostedt , Anthony Liguori , yrl.pp-manager.tt@hitachi.com, Masami Hiramatsu , virtualization@lists.linux-foundation.org Hi Amit, Sorry for the late reply. (2012/07/27 18:43), Amit Shah wrote: > On (Fri) 27 Jul 2012 [17:55:11], Yoshihiro YUNOMAE wrote: >> Hi Amit, >> >> Thank you for commenting on our work. >> >> (2012/07/26 20:35), Amit Shah wrote: >>> On (Tue) 24 Jul 2012 [11:36:57], Yoshihiro YUNOMAE wrote: >> [...] >>>> >>>> ***Just enhancement ideas*** >>>> - Support for trace-cmd >>>> - Support for 9pfs protocol >>>> - Support for non-blocking mode in QEMU >>> >>> There were patches long back (by me) to make chardevs non-blocking but >>> they didn't make it upstream. Fedora carries them, if you want to try >>> out. Though we want to converge on a reasonable solution that's >>> acceptable upstream as well. Just that no one's working on it >>> currently. Any help here will be appreciated. >> >> Thanks! In this case, since a guest will stop to run when host reads >> trace data of the guest, char device is needed to add a non-blocking >> mode. I'll read your patch series. Is the latest version 8? >> http://lists.gnu.org/archive/html/qemu-devel/2010-12/msg00035.html > > I suppose the latest version on-list is what you quote above. The > objections to the patch series are mentioned in Anthony's mails. I'll check the mails. > Hans maintains a rebased version of the patches in his tree at > > http://cgit.freedesktop.org/~jwrdegoede/qemu/ > > those patches are included in Fedora's qemu-kvm, so you can try that > out if it improves performance for you. Thanks. I'll check those patches. >>>> - Make "vhost-serial" >>> >>> I need to understand a) why it's perf-critical, and b) why should the >>> host be involved at all, to comment on these. >> >> a) To make collecting overhead decrease for application on a guest. >> (see above) >> b) Trace data of host kernel is not involved even if we introduce this >> patch set. > > I see, so you suggested vhost-serial only because you saw the guest > stopping problem due to the absence of non-blocking code? If so, it > now makes sense. I don't think we need vhost-serial in any way yet. I understood. We suggested vhost-serial as one of the ideas for improving performances. Other features(trace-cmd, 9pfs, and non-blocking chardev) should be supported first, I think. > BTW where do you parse the trace data obtained from guests? On a > remote host? It is the best that we can parse the data on a remote host in this tracing system. Existing trace-cmd can already parse it on a remote site. If we add the feature collecting event-format data(guest's debugfs has that) from guests, we can parse tracing data on a remote host as well as on a host running guests. Thank you, -- Yoshihiro YUNOMAE Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: yoshihiro.yunomae.ez@hitachi.com