Re: a joint letter on low latency and Linux

Jamie Lokier (lk@tantalophile.demon.co.uk)
Sat, 1 Jul 2000 00:00:20 +0200


>>>(I'll note that on my SMP machine, I'm running MP3 decoders much of the
>>>time, and in practice very rarely hear any dropouts. So the folks who
>>>are painting such a dire picture of the state of Multimedia are
>>>overstating their case a little, I think.)

I'm asking a PCI device for 8 bytes of info every 100us and writing the
numbers to a file over NFS using printf. Works great much, but
occasionally the process stops for several *seconds*. I've seen pauses
5 seconds long, but usually they are only 1 second. (Kernel 2.0.35).

Why is this? We're only writing about 220k of file per second, and the
machine isn't doing anything else. Even if NFS stops for 10 seconds,
the machine has plenty of memory to buffer unwritten data.

-- Jamie

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