On Fri, 2001-10-05 at 06:32, Takashi Iwai wrote:
> At 05 Oct 2001 05:20:40 -0700,
>
> A good news: after several tries and hacks, I got 1msec latency.
> You need to add rescheduling checks in sync_buffers() loop (in
> fs/buffer.c). In my case I added the checks in write_some_buffers()
> and wait_for_buffers(), which are called from sync_buffers().
>
> My results are shown in
> http://www.alsa-project.org/~iwai/latency-results/
> The subdirectory rf-ll2-alsa contains the latest (almost perfect)
> result with 2.4.10 + LL + my patch + ALSA 0.9.0 + reiserfs.
> (No explanatory html, sorry.)
>
Cool! Those graphs are sweeeeet! So are you using Andrew Morton's LL
patch (I notice there is one up on his site now for 2.4.10)? + your
sync_buffers() resched checks. I'll probably give it a try tomorrow
(actually it is tomorrow already, must go to sleep, sun is making things
brighter).
>
> AFAIK there are some tools. I saw some stuffss on Andrew's page.
> For PE kernel, there is additional patch to check the lock time.
> But in both cases the results are not always trustable (only from my
> experience). For example, pe-stats patch shows often sched.c spinlock
> grabs for the longest time, which must not be correct.
>
> Sorry for little useful info. I'd like to know if there is really a
> good tool for this purpose.
>
>
> Takashi
Well that info gives me more of an idea. I would like to get into the
kernel more, I've been fairly confident inserting printks in stuff and
other little debugging hacks, but I would like to get a more in depth
knowledge of it all. Must read more docs and more source :) I'll let you
know of any results I get for 2.4.10 + LL.
--
Josh Green
Smurf Sound Font Editor (http://smurf.sourceforge.net)
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