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From: Tejun Heo <htejun@gmail.com>
To: Mark Lord <liml@rtr.ca>
Cc: jeff@garzik.org, linux-ide@vger.kernel.org, bzolnier@gmail.com
Subject: Re: [PATCH 6/8] libata: adjust speed down rules
Date: Wed, 28 Nov 2007 08:07:10 +0900	[thread overview]
Message-ID: <474CA31E.4000508@gmail.com> (raw)
In-Reply-To: <474C9B10.4060500@rtr.ca>

Hello, Mark.

Mark Lord wrote:
> Tejun Heo wrote:
>> Speed down rules were too conservative.  Adjust them a bit.
>>
>> * More than 10 timeouts can't happen in 5 minutes as command timeout
>>   is 30secs.  Lower the limit for rule #1 to 6.
>>
>> * 10 timeouts is too high for rule #3 too.  Lower it to 6.
>>
>> * SATAPI can benefit from falling back to PIO too.  Allow SATAPI
>>   devices to fall back to PIO.
> ..
> 
> Mmmm...  I see two remaining problems with this:
> 
> -- bad sectors (media errors) will cause inappropriate speed-downs.

No.  Media error is category 0 error which doesn't affect speed down at all.

> -- deliberate (or otherwise) errors via SG_IO will cause inappropriate
> speed-downs.

No, only device errors issued via block layer are considered for speed
down (ATA_QCFLAG_IO).  SG_IO commands will never trigger speed down
unless the error is HSM or timeout.

Thanks.

-- 
tejun

  reply	other threads:[~2007-11-27 23:07 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-27 10:28 [PATCHSET] libata: improve EH speed down logic, take #3 Tejun Heo
2007-11-27 10:28 ` [PATCH 1/8] libata: rearrange ATA_DFLAG_* Tejun Heo
2007-12-01 23:05   ` Jeff Garzik
2007-11-27 10:28 ` [PATCH 2/8] libata: implement protocol tests Tejun Heo
2007-12-01 23:06   ` Jeff Garzik
2007-11-27 10:28 ` [PATCH 3/8] libata: factor out ata_eh_schedule_probe() Tejun Heo
2007-11-27 10:28 ` [PATCH 4/8] libata: move ata_set_mode() to libata-eh.c Tejun Heo
2007-12-01 23:07   ` Jeff Garzik
2007-12-05  1:21     ` Tejun Heo
2007-11-27 10:28 ` [PATCH 5/8] libata: clean up EH speed down implementation Tejun Heo
2007-11-27 10:28 ` [PATCH 6/8] libata: adjust speed down rules Tejun Heo
2007-11-27 22:32   ` Mark Lord
2007-11-27 23:07     ` Tejun Heo [this message]
2007-11-27 23:33       ` Mark Lord
2007-11-27 23:35         ` Tejun Heo
2007-11-28  1:10           ` Mark Lord
2007-11-28  8:30             ` Tejun Heo
2007-11-27 10:28 ` [PATCH 7/8] libata: implement ATA_DFLAG_DUBIOUS_XFER Tejun Heo
2007-11-27 10:28 ` [PATCH 8/8] libata: implement fast speed down for unverified data transfer mode Tejun Heo
2007-12-01 23:07   ` Jeff Garzik
  -- strict thread matches above, loose matches on Subject: below --
2007-11-05  5:45 [PATCHSET] libata: update EH speed down logic, take #2 Tejun Heo
2007-11-05  5:45 ` [PATCH 6/8] libata: adjust speed down rules Tejun Heo
2007-11-01 15:51 [PATCHSET] libata: update EH speed down logic Tejun Heo
2007-11-01 15:51 ` [PATCH 6/8] libata: adjust speed down rules Tejun Heo

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