Date: Thu, 10 Nov 2011 15:40:36 -0800 From: Adrian Chadd <adrian@freebsd.org> To: Jack Vogel <jfvogel@gmail.com> Cc: pyunyh@gmail.com, freebsd-net@freebsd.org, Jason Wolfe <nitroboost@gmail.com>, Emil Muratov <gpm@hotplug.ru>, Hooman Fazaeli <hoomanfazaeli@gmail.com> Subject: Re: Intel 82574L interface wedging on em 7.1.9/7.2.3 when MSIX enabled Message-ID: <CAJ-VmommA0HWWPWYGQQMri9s4GETU%2BYq0qwCpQPT-1nH=A5sUQ@mail.gmail.com> In-Reply-To: <CAFOYbcnVvL1DHxEgfpRjcAH6QpiYwwRZDUiWF%2BRVTx=xhuxgSA@mail.gmail.com> References: <CAAAm0r0RXEJo4UiKS=Ui0e5OQTg6sg-xcYf3mYB5%2Bvk8i8557w@mail.gmail.com> <CAAAm0r1DKvoL9=Ket9up=4%2B5xiCzTTZJK99FhF9jcCA28B0M%2BA@mail.gmail.com> <CAAAm0r3XdsMHZh%2BP_NF-txZasdExzwZ8ymmGQgGhJQds0fOiBQ@mail.gmail.com> <CAAAm0r1iS3z-7CBJ=xYDf%2BJOA1Q2nU0O54Twbyb7FjvgWHjKVw@mail.gmail.com> <4EA7E203.3020306@sepehrs.com> <CAAAm0r3Nr2t8cCetPkFnLQ-3KwqHw_0SpqbtvYPRUkSP=9n8CA@mail.gmail.com> <4EA80818.3030504@sentex.net> <4EA80F88.4000400@hotplug.ru> <4EA82715.2000404@gmail.com> <4EA8FA40.7010504@hotplug.ru> <4EA91836.2040508@gmail.com> <4EA959EE.2070806@hotplug.ru> <4EAD116A.8090006@gmail.com> <CAAAm0r3qm=nQQuAmZDD4k4X8K-xW6_kM9TukRT=1GoG9dYR3zw@mail.gmail.com> <4EAE58A2.9040803@gmail.com> <CAAAm0r0uoPPEQbq5rHkFr6ZLp-WJ4YVjDVvxxV6y%2BUh4eEKDEA@mail.gmail.com> <4EB96511.50701@gmail.com> <CAJ-Vmomf-wxb8dY7YF7qT_FGK5d-YLPU3BkPOeHnOtKZ%2BUrYeQ@mail.gmail.com> <4EBA3F22.2060204@gmail.com> <CAJ-Vmok8kX9F5eXTghx_s7diNiLTWY1-eMDUdCOUHQCz6zW%2BPg@mail.gmail.com> <4EBB9CDF.9090300@gmail.com> <CAJ-VmokfZOHUptqVcfz49ogzk0qCAdSXTO2p8_M=-fAcF4h=1g@mail.gmail.com> <CAFOYbcnVvL1DHxEgfpRjcAH6QpiYwwRZDUiWF%2BRVTx=xhuxgSA@mail.gmail.com>
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In the case of multi-threaded OACTIVE, why not just do this: upon queue completion: * lock; * do queue completion; * if any frames were completed, clear queue busy; * if (queue busy == clear && OACTIVE) clear OACTIVE; * run queue completion; * unlock. upon queue transmit: * lock; * queue frame; * if (fail) - mark queue as busy; * if (all busy) - set OACTIVE. * unlock The stack will stop sending you frames whilst OACTIVE Is set, but will continue sending them when you clear it. If you just clear OACTIVE when _a_ queue is clear then you'll get frames queued via start/transmit when queues are busy, but what you won't do is starve them all until all queues have free slots. Ie, you don't mind clearing it, then getting a frame and immediately finding you're busy. Once you've done that, any further issues are likely either concurrency with accessing the tx/rx descriptor rings (per-queue), or the interrupt handling races. Ie, you disable interrupts, handle the tx queue completion, -then- re-enable interrupts and clear masks. Maybe that logic in igb_enable_intr() is to blame? Ie, que_mask / link_mask, is that before or after the queue has been handled? If it's called after the queue is handled, and que_mask / link_mask is 0, but the queue is full, you'll never pick up the next interrupt as there won't be one? 2c, Adrianhome | help
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