Re: [PATCH] sata_sx4: speed up ECC initialization

[Jeff Garzik <jeff@garzik.org>]

Alexander Beregalov wrote:
> 2009/4/15 Jeff Garzik <jeff@garzik.org>:
>> Alexander Beregalov wrote:
>>> On Tue, Apr 14, 2009 at 07:57:57AM -0400, Jeff Garzik wrote:
>>>> Alexander Beregalov wrote:
>>>>> ECC initialization takes too long. It writes zeroes by portions of 4
>>>>> byte, it takes more than 6 minutes to initialize 512Mb DIMM module.
>>>>> Change portion to 1Mb.
>>>>>
>>>>> before:
>>>>> [10857.207576] pdc20621_dimm_init: Start ECC initialization
>>>>> [11235.333118] pdc20621_dimm_init: Finish ECC initialization
>>>>>
>>>>> after:
>>>>> [ 1005.126437] pdc20621_dimm_init: Local DIMM Speed = 100
>>>>> [ 1005.128111] pdc20621_dimm_init: Local DIMM Size = 512MB
>>>>> [ 1005.133508] Local DIMM ECC Enabled
>>>>> [ 1005.236482] pdc20621_dimm_init: Start ECC initialization
>>>>> [ 1031.278098] pdc20621_dimm_init: Finish ECC initialization
>>>>>
>>>> Comments:
>>>>
>>>> 1) on an older machine, where these things might be found, 1MB might be a
>>>> lot -- particularly if there is a lot of VM fragmentation.  Please reduce
>>>> the size a bit -- I suppose 128k is not unbearably slow?
>>>>
>>>> 2) Rather than repeating 'page size * 32' calculation multiple times, put
>>>> it into a named constant somewhere.
>>>>
>>>> Other than that, looks ok!
>>>
>>>> From 00e980a4651ef12811fbe9a893a7e72510b955d1 Mon Sep 17 00:00:00 2001
>>> From: Alexander Beregalov <a.beregalov@gmail.com>
>>> Date: Tue, 14 Apr 2009 23:55:52 +0400
>>> Subject: [PATCH v2] sata_sx4: speed up ECC initialization
>>>
>>> ECC initialization takes too long. It writes zeroes by portions
>>> of 4 byte, it takes more than 6 minutes on my machine to initialize
>>> 512Mb ECC DIMM module. Change portion to 128Kb - it significantly
>>> reduces initialization time.
>>>
>>> Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
>>> ---
>>>  drivers/ata/sata_sx4.c |   11 +++++++----
>>>  1 files changed, 7 insertions(+), 4 deletions(-)
>>
>> Applied, to libata-dev.git#upstream
>>
>> Thanks!
>>
>> So...   the $64,000 question:  does sata_sx4 work for you?
> 
> No, not yet! :)
> It works without disks ;)
> It has found disks, but got timeout from them.
> Some specific functions should be added to ops structure.
> 
> At first I am trying to understand how to detect cable type.
> I have two examples: from Promise partial source code and from FreeBSD.
> 
> But PGuide says the chip automatically detects cable type.
> Does it mean the driver should not do anything with it? - I will try it.

Check out 2.6.30-rc6, sata_sx4 received several major bug fixes...

	Jeff