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SubjectRe: VST patches ported to 2.6.11-rc1
Pavel Machek wrote:
> Hi!
>
>
>>I really hate sf download system... Here are those patches (only
>>common+i386) ported to 2.6.11-rc1.
>
>
> Good news is it booted. But I could not measure any powersavings by
> turning it on. (I could measure difference between HZ=100 and
> HZ=1000).
>
> Hmm, it does not want to do anything. threshold used to be 1000, does
> it mean that it would not use vst unless there was one second of quiet
> state? I tried to lower it to 10 ("get me HZ=100 power consumption")
> but it does not seem to be used, anyway:
>
> root@amd:/proc/sys/kernel/vst# cat successful_vst_exit
> 0
> root@amd:/proc/sys/kernel/vst# cat external_intr_exit
> 0
> root@amd:/proc/sys/kernel/vst#

Hm.. and this after you lowered the threshold? The skipped interrupts should
also be of interest...
>
>
>>+config HIGH_RES_RESOLUTION
>>+ int "High Resolution Timer resolution (nanoseconds)"
>>+ depends on HIGH_RES_TIMERS
>>+ default 1000
>>+ help
>>+ This sets the resolution in nanoseconds of the CLOCK_REALTIME_HR and
>>+ CLOCK_MONOTONIC_HR timers. Too fine a resolution (small a number)
>>+ will usually not be observable due to normal system latencies. For an
>>+ 800 MHz processor about 10,000 (10 microseconds) is recommended as a
>>+ finest resolution. If you don't need that sort of resolution,
>>+ larger values may generate less overhead.
>
>
> Ugh, if minimum recomended value is 10K, why does it have 1K as a
> default?

I think I have this wrong. I usually set it to 10 for my testing. I need to
look over the conversion code and such to see just what the units are...

>
>
>>+ The system boots with VST enabled and it can be disabled by:
>>+ "echo 0 > /proc/sys/kernel/vst/enable".
>
>
> It definitely booted with vst disabled here... echo 1 did the trick
> through.

I missed that. Yes we want to boot with it disabled. It can upset some of the
boot up code otherwise.
>
>
>>short_timer_fns This is an array of 5 entries of the form
>>...
>> 0xc110ea80 when the timer expires.
>>Both of these arrays are kept as circular lists and read back such
>>that
>>the latest entry is presented to the reader first. The entries are
>>cleared when read.
>
>
> ...it is bad idea to have them world-readable, then.

This is diagnostic code for the kernel dude who wants to know why he is not
getting the VST sleeps he wants. Seems a bit harsh to make him be root to see
it....

--
George Anzinger george@mvista.com
High-res-timers: http://sourceforge.net/projects/high-res-timers/

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