Date:	Sun, 07 Sep 2008 12:35:20 +0200
From:	Anders Aagaard <aagaande@...il.com>
To:	suspend-devel@...ts.sourceforge.net
CC:	linux-kernel@...r.kernel.org
Subject: Re: [Suspend-devel] Resume performance

Rafael J. Wysocki wrote:
> On Friday, 5 of September 2008, Anders Aagaard wrote:
>> Rafael J. Wysocki wrote:
>>> On Friday, 5 of September 2008, Anders Aagaard wrote:
>>>> Hi
>>> Hi,
>>>
>>> This is a kernel problem, so let's CC the LKML.
>>>
>>>> I have a intel P35 board with a quad core cpu in it, it's currently 
>>>> running as a server for a small network, and I'd like to be able to shut 
>>>> it down when idle, and use wake on lan to wake it up when it's needed. 
>>>> Now I got that part working quite well, but for some reason I have a 
>>>> long delay in resume.
>>>>
>>>> I seem to remember being able to resume this computer in 2-3 seconds 
>>>> when I was testing it, now it needs 35 seconds to resume.  It seems 
>>>> regardless of resume options used, and it always resumes to a working 
>>>> state without problems.
>>> What kernel are you using at the moment and which one was used for the
>>> testing?
>> I'm using gentoo's 2.6.25-r7, I've also tried vanilla sources.
> 
> Would it be possible to test 2.6.27-rc5-gi7 from kernel.org?

Tested, makes no difference.

> 
>>>> I've tried quite a lot of things, booting with noapic/nosmp, booting a 
>>>> kernel without usb/network drivers, disabling ahci (using ata_piix 
>>>> driver instead of ahci), and there's always that one long delay.  And 
>>>> I'm not quite sure how the kernel printk timing information works, so 
>>>> I'm not sure whats causing that delay.
>>>>
>>>> Output from dmesg when booting with nosmp (to get accurate timing data):
>>>> scripts/show_delta -b "Force enabled HPET at resume"
>>>> [349.821150 < 7.039261 >] ata3.00: configured for UDMA/133
>>>> [349.821160 < 7.039271 >] sd 2:0:0:0: [sdc] 976773168 512-byte hardware 
>>>> sectors (500108 MB)
>>>> [349.821165 < 7.039276 >] sd 2:0:0:0: [sdc] Write Protect is off
>>>> [349.821166 < 7.039277 >] sd 2:0:0:0: [sdc] Mode Sense: 00 3a 00 00
>>>> [349.821173 < 7.039284 >] sd 2:0:0:0: [sdc] Write cache: enabled, read 
>>>> cache: enabled, doesn't support DPO or FUA
>>>> [349.972801 < 7.190912 >] ata1: SATA link up 3.0 Gbps (SStatus 123 
>>>> SControl 300)
>>>> [349.979060 < 7.197171 >] ata1.00: configured for UDMA/133
>>>> [349.979070 < 7.197181 >] sd 0:0:0:0: [sda] 976771055 512-byte hardware 
>>>> sectors (500107 MB)
>>>> [349.979075 < 7.197186 >] sd 0:0:0:0: [sda] Write Protect is off
>>>> [349.979076 < 7.197187 >] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
>>>> [349.979083 < 7.197194 >] sd 0:0:0:0: [sda] Write cache: enabled, read 
>>>> cache: enabled, doesn't support DPO or FUA
>>> It looks like this happens here.  Can you try to unload the network driver
>>> before suspend, please?
>> I tried to build a kernel without it, and it still takes the exact same 
>> amount to boot, I've also tried unloading usb drivers and it takes the 
>> exact same amount of time.
> 
> Can you try to boot with init=/bin/bash and suspend to RAM?  (Please have a
> look at section 2 of Documentation/power/basic-pm-debugging.txt in the newer
> kernel sources).

I checked without X before, but forgot to unload the nvidia module, that 
apparently makes a big difference, I did some numbers with 
scripts/show_delta -b "Back to C".

Nvidia and X : 32 seconds
No X (same result as booting with init=/bin/bash) : 8.3 seconds
Git kernel : 8.2 seconds
Light kernel (no sound, network card and usb drivers) : 8.17 seconds
ATI card instead of nvidia : 8.22 seconds

I think we found the problem, I already replaced nvidia hardware in one 
computer to resolve another issue.  Really appreciate your help on this 
issue, this resume time works pretty well for me, it was a bit 
ridiculous when I could boot faster than resume.

Is 8 seconds fairly expected?  My other computer (same ati card) boots 
in about 2 seconds, but there's a lot less hardware in it (6 hd's and a 
ton of usb devices in one computer, 1 hd and 1 usb device in the other). 
  I checked cold booting with and without usb devices, my light kernel 
boots to /bin/bash in 2.5 seconds, normal kernel about 7-8.  But I dont 
see anything about usb on resume.

Thanks a lot, Anders


> 
> Thanks,
> Rafael
> 

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