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From: "Patro, Sumant" <>
To: "James Bottomley" <>
Cc: <>, <>,
	"Kolli, Neela" <>,
	"Yang, Bo" <>
Subject: RE: [PATCH] scsi: megaraid_sas - throttle io if cmds are in riskof being timed-out
Date: Mon, 19 Mar 2007 17:08:54 -0600	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Thank you James.
I will submit new patch that will throttle (if required) from
eh_timed_out call back.



-----Original Message-----
From: James Bottomley [] 
Sent: Friday, March 16, 2007 3:23 PM
To: Patro, Sumant
Cc:;;; Kolli, Neela; Yang, Bo
Subject: Re: [PATCH] scsi: megaraid_sas - throttle io if cmds are in
riskof being timed-out

On Thu, 2007-03-01 at 13:29 -0800, Sumant Patro wrote:
> Driver to throttle IO to reduce risk of OS timing out cmds.
> Implemented a circular queue to keep track of pending OS cmds in FW. 
> This queue is periodically (every 10 sec) checked by a timer routine.
> If there is any cmd that is in risk of getting timed-out by the OS, 
> the host->can_queue is reduced to 16 and MEGASAS_FW_BUSY flag is set.
> The host->can_queue will be restored to default value when the 
> following two conditions are met : 5 secs has elapsed and the # of 
> outstanding cmds in FW is less than 17.
> Also increased the per cmd timeout to 120*HZ from 90*HZ.

OK, this is still not nice.  What you need to be doing is intercepting
the timeout before it fires (and quiesces the machine).  Currently the
eh_timed_out() callback is only exposed to transport classes, I'll put
it back into the host template and then you can use it.


      reply	other threads:[~2007-03-19 23:09 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-01 21:29 [PATCH] scsi: megaraid_sas - throttle io if cmds are in risk of being timed-out Sumant Patro
2007-03-16 22:22 ` James Bottomley
2007-03-19 23:08   ` Patro, Sumant [this message]

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