From owner-freebsd-arch@FreeBSD.ORG Thu Jan 22 22:41:30 2015 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id BEC8C6DA for ; Thu, 22 Jan 2015 22:41:30 +0000 (UTC) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:1900:2254:206c::16:87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 9A59CF3A for ; Thu, 22 Jan 2015 22:41:30 +0000 (UTC) Received: from freefall.freebsd.org (localhost [127.0.0.1]) by freefall.freebsd.org (8.14.9/8.14.9) with ESMTP id t0MMfUAg055635 for ; Thu, 22 Jan 2015 22:41:30 GMT (envelope-from bdrewery@freefall.freebsd.org) Received: (from bdrewery@localhost) by freefall.freebsd.org (8.14.9/8.14.9/Submit) id t0MMfUj1055631 for freebsd-arch@freebsd.org; Thu, 22 Jan 2015 22:41:30 GMT (envelope-from bdrewery) Received: (qmail 25414 invoked from network); 22 Jan 2015 16:41:26 -0600 Received: from unknown (HELO ?10.10.1.139?) (freebsd@shatow.net@10.10.1.139) by sweb.xzibition.com with ESMTPA; 22 Jan 2015 16:41:26 -0600 Message-ID: <54C17CA5.9060703@FreeBSD.org> Date: Thu, 22 Jan 2015 16:41:41 -0600 From: Bryan Drewery Organization: FreeBSD User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Konstantin Belousov , Hans Petter Selasky Subject: Re: [RFC] kern/kern_timeout.c rewrite in progress References: <54B29A49.3080600@selasky.org> <54B67DA7.3070106@selasky.org> <54B7DECF.8070209@selasky.org> <54BADFB3.3030405@selasky.org> <54BE03EB.2070604@selasky.org> <20150120104736.GA78629@zxy.spb.ru> <54C0CE09.500@selasky.org> <20150122102740.GZ42409@kib.kiev.ua> In-Reply-To: <20150122102740.GZ42409@kib.kiev.ua> OpenPGP: id=6E4697CF; url=http://www.shatow.net/bryan/bryan2.asc Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="V8R6iQUN5gKR6jDkMvLB0xg2tvPakJXN1" Cc: FreeBSD Current , "freebsd-arch@freebsd.org" X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Jan 2015 22:41:30 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --V8R6iQUN5gKR6jDkMvLB0xg2tvPakJXN1 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 1/22/2015 4:27 AM, Konstantin Belousov wrote: > On Thu, Jan 22, 2015 at 11:16:41AM +0100, Hans Petter Selasky wrote: >> On 01/20/15 11:47, Slawa Olhovchenkov wrote: >>> On Tue, Jan 20, 2015 at 08:29:47AM +0100, Hans Petter Selasky wrote: >>> >>>> On 01/17/15 23:18, Hans Petter Selasky wrote: >>>>> On 01/17/15 20:11, Jason Wolfe wrote: >>>>>> >>>>>> HPS, >>>>>> >>>>>> Just to give a quick status update, this patch has most certainly >>>>>> resolved our spin lock held too long panics on stable/10. >>>>>> >>>>>> Thank you to JHB for spending some time digging into the issue and= >>>>>> leading us to td_slpcallout as the culprit, and HPS for your rewri= te. >>>>>> I had heard rumors of other being affected by similar issues, so t= his >>>>>> seems like a fine candidate for an MFC if possible. >>>>>> >>>>>> Jason >>>>>> >>>>> >>>>> Hi Jason, >>>>> >>>>> I'm glad to hear that my patch has resolved your issue and I'm happ= y we >>>>> now have a more stable system. >>>>> >>>>> It was actually a co-worker at work which wrote some bad code which= I >>>>> started debugging which then lead me to look at the callout subsyst= em. >>>>> One bug kills the other ;-) >>>>> >>>>> I'm planning a MFC to 10-stable - yes, and will possibly add the >>>>> _callout_stop_safe() function to not break binary compatibility wit= h >>>>> existing drivers as part of the MFC. >>>>> >>>>> --HPS >>>> >>>> Hi, >>>> >>>> Here is a followup patch for the TCP stack like I mentioned in the >>>> beginning of the work done on the callout subsystem: >>>> >>>> https://reviews.freebsd.org/D1563 >>>> >>>> If someone has a setup for massive TCP testing please give it a spin= =2E >>> >>> I have on 10.1 (with applied r261906). >> >> FYI: >> >> r277213 is going to be pulled out from -current in at maximum a few=20 >> hours from now, because developers need more time to review patches in= =20 >> surrounding areas like the TCP stack area to restore distribution of=20 >> callouts on multiple CPUs when using MPSAFE callouts to avoid congesti= on=20 >> in the TCP stack. >=20 > No, r277213 was requested to be reverted not due to TCP issues. >=20 > The main complain is that you left indefinite amount of cases degraded,= > and there is no analysis of each such case, nor even a list of the case= s > that need to be fixed (or argumentation why consumer of the callout KPI= > could be left as is). >=20 > Just providing fix for one place is not enough. I have a similar concern about out-of-tree work. It would be surprising for a vendor or module developer to find their performance degrade if they missed accounting for this change. At a minimum, an UPDATING entry should be added explaining the change and what must be done for consumers= =2E --=20 Regards, Bryan Drewery --V8R6iQUN5gKR6jDkMvLB0xg2tvPakJXN1 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBAgAGBQJUwXylAAoJEDXXcbtuRpfP7dkIAM2nPjOqScYn2BhbXYckptZz fjScHRVBYGP03MCP1GGM6Jncr9uQrrzoOdp+8Bmn1ezquSdl5i7sLmVedVpuFKtP PzICFgl0pPkVie1ixByCqJ4ADiADmSU5sxOaDFOvQXtRaPEviHUnrhBaTWItHdEP ZUA8cHvzBgT2MXCmTCdFPnFJfxn3Ap+yvzL6lrgLuq+fVJNc23jTtRg12ipVzgGs LorIxFz/PUmrQ1tl8rb8ODk8rbeFQXiPCTMXHrFB0E6EGzrKQo6vRSLWAg7X2wQT xh+CReBtmRSNrP7C28ShBg5RmQVYzpurPFX+FWEMuqfGVbAiJzYRQozp1vSn0lI= =sTj3 -----END PGP SIGNATURE----- --V8R6iQUN5gKR6jDkMvLB0xg2tvPakJXN1--