Date: Thu, 22 Jan 2015 16:41:41 -0600 From: Bryan Drewery <bdrewery@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com>, Hans Petter Selasky <hps@selasky.org> Cc: FreeBSD Current <freebsd-current@freebsd.org>, "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org> Subject: Re: [RFC] kern/kern_timeout.c rewrite in progress Message-ID: <54C17CA5.9060703@FreeBSD.org> In-Reply-To: <20150122102740.GZ42409@kib.kiev.ua> References: <CAAAm0r39Sv3TCvwaCiNQ1Y9iBVtY_nb0A_iNOC41bgxqXmt%2B4w@mail.gmail.com> <54B29A49.3080600@selasky.org> <CAAAm0r2eNYicq%2BKKj5f5EE%2BKLPxdvy15wj1ZWS=zA6sgOtcoGQ@mail.gmail.com> <54B67DA7.3070106@selasky.org> <54B7DECF.8070209@selasky.org> <CAAAm0r0S=s8pRHR3-h%2BntEt27cw6tshHCONSezaAr3zBhLhSWA@mail.gmail.com> <54BADFB3.3030405@selasky.org> <54BE03EB.2070604@selasky.org> <20150120104736.GA78629@zxy.spb.ru> <54C0CE09.500@selasky.org> <20150122102740.GZ42409@kib.kiev.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
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--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?54C17CA5.9060703>