Date: Fri, 23 Jun 2006 10:18:33 -0600 From: "Justin T. Gibbs" <gibbs@scsiguy.com> To: Volodymyr Kostyrko <arcade@synergetica.dn.ua> Cc: freebsd-scsi@freebsd.org Subject: Re: ahd(4) poor performance Message-ID: <5272604BA34A45926DFA0D2F@[10.0.0.22]> In-Reply-To: <449C0E34.3080005@synergetica.dn.ua> References: <4499B748.6040805@synergetica.dn.ua> <90D11403BD2140875BFEB24D@[10.0.0.22]> <449C0E34.3080005@synergetica.dn.ua>
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dd is synchronous. You'd need to aggregate the throughput of several dd operations to see the impact of overlapped commands. -- Justin --On Friday, June 23, 2006 6:52 PM +0300 Volodymyr Kostyrko <arcade@synergetica.dn.ua> wrote: > Justin T. Gibbs ?????: >> --On Thursday, June 22, 2006 12:16 AM +0300 Volodymyr Kostyrko >> <arcade@synergetica.dn.ua> wrote: >> >>> Hi all. >>> >>> I have: >>> >>> ahd0: <Adaptec (Dell OEM) 39320 Ultra320 SCSI adapter> port >>> 0xdc00-0xdcff,0xd800-0xd8ff mem 0xdfbfe000-0xdfbfffff irq 66 at device >>> 7.0 on pci3 >>> ahd0: [GIANT-LOCKED] >>> aic7902: Ultra320 Wide Channel A, SCSI Id=7, PCI-X 101-133Mhz, 512 SCBs >>> ahd1: <Adaptec (Dell OEM) 39320 Ultra320 SCSI adapter> port >>> 0xd400-0xd4ff,0xd000-0xd0ff mem 0xdfbfc000-0xdfbfdfff irq 67 at device >>> 7.1 on pci3 >>> ahd1: [GIANT-LOCKED] >>> aic7902: Ultra320 Wide Channel B, SCSI Id=7, PCI-X 101-133Mhz, 512 SCBs >>> >>> Booting machine also results in: >>> >>> ahd0: Invalid Sequencer interrupt occurred. >> >> This error is benign. >> >> There have been issues reported with some recent Seagate drives and >> large queue depths. You may get better performance if you use camcontrol >> to lower the queue depth to 63 or 32. I believe that 32 is the default >> used by Linux. >> >> -- >> Justin > > Interesting. > > By default I have the following: > > srv4# camcontrol tags 0:0 -v > (pass1:ahd0:0:1:0): dev_openings 1 > (pass1:ahd0:0:1:0): dev_active 0 > (pass1:ahd0:0:1:0): devq_openings 1 > (pass1:ahd0:0:1:0): devq_queued 0 > (pass1:ahd0:0:1:0): held 0 > (pass1:ahd0:0:1:0): mintags 2 > (pass1:ahd0:0:1:0): maxtags 255 > > Raising this to higher values provides better perfomance: > > @1: > > > dd if=/dev/zero of=somefile count=20480 > 20480+0 records in > 20480+0 records out > 10485760 bytes transferred in 1.114188 secs (9411123 bytes/sec) > > @2: > > > dd if=/dev/zero of=somefile count=20480 > 20480+0 records in > 20480+0 records out > 10485760 bytes transferred in 0.402884 secs (26026747 bytes/sec) > > Raising it further doesn't help anyway. And it still behaves not so > fast as Linux. > > -- > [WBR], Arcade. >
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