Subject: Re: [linux-audio-dev] lowish-latency patch and toolchain
From: yodaiken_AT_fsmlabs.com
Date: Sun Jul 09 2000 - 05:43:13 EEST
On Sun, Jul 09, 2000 at 01:25:30AM +0400, Khimenko Victor wrote:
> In <20000708203335Z4895-532+18680_AT_nic.funet.fi> Juhana Sadeharju (kouhia_AT_nic.funet.fi) wrote:
> > It would be very silly to talk that Linux would have 1 ms latency
> > if it reaches it only once a week.
>
> Hmm. Why not ?
Please remember that "once a week" is pretty vague. "once a week"
during what load, with what variance, ...
Suppose Linux will, once every now and then have
5 millisecond latency 10 times over a 2 minute period, but then go
"typically" three weeks before going over 4 milliseconds. Is that ok?
> casing big delays). Have you ever written ANY program for Windows 3.x ? It's
> basically the same problem. May be non-preeemptive linux kernel is bad thing
> for current world and may be it can be even fixed. Just not this close to
> 2.4 release: it's HUGE change.
There is a good reason why Linux and other kernels as designed to be
non-preemptive. To allow preemption, you must introduce locks around
all critical data structures and these locks both can cause bugs and
certainly add overhead -- especially in today's highly cached processors.
-- --------------------------------------------------------- Victor Yodaiken FSMLabs: www.fsmlabs.com www.rtlinux.com FSMLabs is a servicemark and a service of VJY Associates L.L.C, New Mexico.
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