Date: Mon, 7 Dec 2009 20:05:00 -0500 From: Jung-uk Kim <jkim@FreeBSD.org> To: Scott Long <scottl@samsco.org> Cc: Alexander Sack <pisymbol@gmail.com>, scottl@FreeBSD.org, freebsd-current@FreeBSD.org, emaste@FreeBSD.org Subject: Re: aac(4) resource FIB starvation on BUS scan revisited Message-ID: <200912072005.02662.jkim@FreeBSD.org> In-Reply-To: <D7DDDA30-44B2-4E84-9F52-42DD2C43DC62@samsco.org> References: <3c0b01820912071342u1c722b2clf9c8413e40097279@mail.gmail.com> <200912071931.46002.jkim@FreeBSD.org> <D7DDDA30-44B2-4E84-9F52-42DD2C43DC62@samsco.org>
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On Monday 07 December 2009 07:47 pm, Scott Long wrote: > On Dec 7, 2009, at 5:31 PM, Jung-uk Kim wrote: > > On Monday 07 December 2009 05:30 pm, Alexander Sack wrote: > >> On Mon, Dec 7, 2009 at 4:42 PM, Alexander Sack > >> <pisymbol@gmail.com> > > > > wrote: > >>> Folks: > >>> > >>> I posted a similar thread on freebsd-scsi only to realize that > >>> scottl had fixed my first issue during some MP CAM cleanup with > >>> respect to a race during resource allocation issues on a later > >>> version of the driver we are using (I believe we did the same > >>> thing to resolve a lock issue on bootup). > >>> > >>> However on my RELENG_8 box with (2) Adaptec 5085s connected to > >>> some JBODs (9TB each) I still have a FIB starvation issue > >>> during the LUN scan: > >>> > >>> The number of FIBs allocated to this card is 512 (older cards > >>> are 256). The max_target per bus is 287. On a six channel > >>> controller with a BUS scan done in parallel I see a lot of > >>> this: > >>> > >>> ... > >>> (probe501:aacp1:0:214:0): Request Requeued > >>> (probe501:aacp1:0:214:0): Retrying Command > >>> (probe520:aacp1:0:233:0): Request Requeued > >>> (probe520:aacp1:0:233:0): Retrying Command > >>> (probe528:aacp1:0:241:0): Request Requeued > >>> (probe528:aacp1:0:241:0): Retrying Command > >>> (probe540:aacp1:0:253:0): Request Requeued > >>> (probe540:aacp1:0:253:0): Retrying Command > >>> (probe541:aacp1:0:254:0): Request Requeued > >>> (probe541:aacp1:0:254:0): Retrying Command > >>> .... > >>> > >>> I think the driver is much happier with the following attached > >>> patch (with dmesg). > >> > >> Patch again but this time not base-64 encoded: > > > > [SNIP!] > > > > I want it to be little conservative here, i.e., pre-allocating > > half of max_fibs. Will the attached patch work for you? > > The FIB allocation scheme was written when it was common for > machines to only have 64MB of RAM and proportionally less KVA, so > 256KB or 512KB was a lot of RAM to wire down. Those days have > probably passed. So, what would do if you were hypothetically rewriting it today? :-) Jung-uk Kim
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