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From: Jeff Garzik <jgarzik@pobox.com>
To: Albert Lee <albertcc@tw.ibm.com>
Cc: Linux IDE <linux-ide@vger.kernel.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Doug Maxey <dwm@maxeymade.com>,
	Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Subject: Re: [PATCH 2/3] libata-dev: pdc2027x mdelay() problem fix for power5 micro-partitioning
Date: Wed, 10 Aug 2005 23:04:47 -0400	[thread overview]
Message-ID: <42FAC04F.4060405@pobox.com> (raw)
In-Reply-To: <42F251C2.8090409@tw.ibm.com>

Albert Lee wrote:
> Jeff,
> 
> Patch 2/3: pdc2027x mdelay() problem fix for micro-partitioning
> 
> Description:
>   The mdelay(100) does not delay exactly 100 ms on IBM power5 machines 
> when the power5 CPU micro-partitioning feature is turned on.
> Ex. If micro-partitioning is set to use 0.1 of the CPU time, mdelay(100) 
> will delay about 1 sec instead of 100ms.
> 
> Changes:
>  - Use do_gettimeofday() to measure the actual elapsed time.
>  According to the documentation, do_gettimeofday() works on most platforms
> except some old M68K machines. There are no PCI slots on M68K machines,
> so using do_gettimeofday() seems to be safe here.

NAK.

mdelay() should be investigated as to why its not working on your 
platform.  do_gettimeofday() is -less- granular and accurate than 
mdelay(), usually.

	Jeff


  parent reply	other threads:[~2005-08-11  3:04 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-08-04 17:17 [PATCH 0/3] libata-dev: pdc2027x fixes Albert Lee
2005-08-04 17:32 ` [PATCH 1/3] libata-dev: Convert pdc2027x from PIO to MMIO Albert Lee
2005-08-04 19:40   ` Brett Russ
2005-08-09 11:04     ` Albert Lee
2005-08-11  2:37     ` Jeff Garzik
2005-08-11  3:03   ` Jeff Garzik
2005-08-11  9:49     ` Albert Lee
2005-08-11 17:49       ` Jeff Garzik
2005-08-04 17:34 ` [PATCH 2/3] libata-dev: pdc2027x mdelay() problem fix for power5 micro-partitioning Albert Lee
2005-08-07  9:18   ` Benjamin Herrenschmidt
2005-08-11  3:04   ` Jeff Garzik [this message]
2005-08-11  8:36     ` Benjamin Herrenschmidt
2005-08-11  9:52       ` Albert Lee
2005-08-04 17:39 ` [PATCH 3/3] libata-dev: Fix pdc2027x ATAPI DMA lost irq problem Albert Lee
2005-08-04 18:41   ` Doug Maxey
2005-08-11  3:05   ` Jeff Garzik

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