My initial idea was to execute only block device resume on the separate
thread, as it take almost 80% of the total device resume time ( I did
detailed profile of each device resume through rdtsc() counter) and rest
of them takes less than 20% in total( each device ( including char and
net)on its own takes less than 0.03 seconds). I could still save some
good amount of resume time ( apprx 1.2 sec). However Given this ratio,
and the fact that block device resume happening way at the end of the
list, I tried this with only taking care of Block devices.
I am not sure if there is a case where any scenario where Char
devices would take more resume time than normally it would. If so I can
modify the patch to put only block devices in separate thread for resume
Thanks
-hari
-----Original Message-----
From: Pavel Machek [mailto:[email protected]]
Sent: Friday, January 19, 2007 3:00 PM
To: Seshadri, Harinarayanan
Cc: [email protected]; [email protected];
[email protected]
Subject: Re: [RFC] [PATCH] Power S3 Resume Optimization Patch. Request
for Comment
Hi!
> [RFC][PATCH] Power S3 Resume optimisation
> Here is a simple patch for optimising the S3 resume. With this
> patch the resume time is 0.85. Given the fact that device
initialisation
> on the resume takes almost 70% of time, By executing the whole
> "device_resume()" function on a seperate kernel thread, the resume
gets
> completed( ie. the user can precieve) by ~0.85 sec.
Yep, but you also break it completely...
> To avoid any possible race condition while processing the IO
> request and to make sure all the io request are queued till the device
> resume thread exits, the IO schedulars (patched cfq and as) checks a
for
> system_resume flag, which is set when the device resume thread starts,
> if the flag is set, it doesnt put the request in the dispatch queue.
> Once the flag is cleared i.e when the device resume thread is
complete,
> the IO-schedular behave as in normal situation.
And you noticed that, so you fixed obvious problems on block devices.
Ignoring char and net devices completely.
> @@ -1088,6 +1088,19 @@
> if (list_empty(&ad->fifo_list[adir]))
> return 0;
>
> + /*
> + * Check here for the System resume flag to be cleared, if
flag
> is
> + * still set the resume thread hasnt completed yet, and hence
> dont
> + * takeout any new request from the FIFO
> + */
> + extern int system_resuming;
> + if (system_resuming != 0)
> + {
Locking. CodingStyle.
> -static void suspend_finish(suspend_state_t state)
> +static int dev_resume_proc(void * data)
> {
> + /* Set the global resume flag, this will be checked by the
> IO_schedular
Broken mail client.
> + * before dispatching the IO request
> + */
> + system_resuming =1;
Add mdelay(1 hour) here. Then try to use your wifi card and your tv
grabber.
> device_resume();
> + system_resuming = 0;
> +#ifdef DEBUG
> + printk(" reseting system_resume \n");
> +#endif
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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