quoted
quoted
quoted
You might want to try Andrew Morton's Low-Latency patch (URL:
http://www.uow.edu.au/~andrewm/linux/schedlat.html#downloads)
Done. It doen't make a lot difference, but I can compile stuff without
sound interruptions most of the time
OK. So nothing much has changed since I last tried it - note that those
patches take scheduling latency below 1ms on x86.
maybe we do have some IRQ blocking as well (I haven't had time to benchmark
that at 2.4.x - it's on the TODO list).
(if it doesn't involve libtool).
hmmm. Have you got any idea what libtool does that is different?
(does strace work at the moment?)
mmap-ing files is "bad news" even with the LL patches (IIRC).
I tried to lower the fragment size to 9 (512B==0.012s) and it skips
even when the system is completely idle.
I don't know what UI you are using but...
does this occur each second (i.e. related to, for example, updating a clock
on screen) ... or
every 20/30 seconds or so - perhaps related to sync() ?
---
ah well, we'll solve it eventually [otherwise PPC is dead for sound - which
would be a Great Shame (tm).]
ciao,
Iain.
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OK. So nothing much has changed since I last tried it - note that those
patches take scheduling latency below 1ms on x86.
This means the bad code is in the "small" arch-dependdent part
of the kernel.
maybe we do have some IRQ blocking as well (I haven't had time to benchmark
that at 2.4.x - it's on the TODO list).
quoted
(if it doesn't involve libtool).
hmmm. Have you got any idea what libtool does that is different ?
Not yet. I'll look for it ASA I have time.
(does strace work at the moment?)
Yes it does. The only uncommon thing I can see is a huge number of
calls to rt_sigprocmask().
mmap-ing files is "bad news" even with the LL patches (IIRC).
I didn't know that.
quoted
I tried to lower the fragment size to 9 (512B==0.012s) and it skips
even when the system is completely idle.
I don't know what UI you are using but...
I wrote a small prog to play aiffs from disk.
does this occur each second (i.e. related to, for example, updating a clock
on screen) ... or
every 20/30 seconds or so - perhaps related to sync() ?
I don't know... It seems quite random, but I have some stuff running in
the taskbar. I'll check better.
Bye.
Giuliano Pochini ->)|(<- Shiny Network {AS6665} ->)|(<-
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
quoted
(if it doesn't involve libtool).
hmmm. Have you got any idea what libtool does that is different ?
(does strace work at the moment?)
The only unusual thing strace shows is thai it calls rt_sigprocmask()
hundred times. rt_sigprocmask() stops irqs for a very short time. A
prog that calls it 1M time shows this is not what I'm looking for.
I searched in all /arch/ppc for something interesting... nothing. I
definitely need a tool to measure how much time the various
spinlock_irq's are hold.
mmap-ing files is "bad news" even with the LL patches (IIRC).
strace libtool shows 13 lines like this:
mmap(ptrace: umoven: input/output error
) = 0x30019000
I don't know what does it mean.
Bye.
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