Subject: Re: [linux-audio-dev] latency report
From: Dave Phillips (dlphilp_AT_bright.net)
Date: Fri Nov 17 2000 - 17:02:48 EET
Greetings:
That's great news, Paul. As I mentioned in a post to the Ardour list,
the O'Reilly Network will be running an article I wrote on he
low-latency topic. It includes the results of tests made on the 2.2.10,
2.2.17, and 2.4.0-test9 kernels, patched and unpatched, with tuned and
untuned disks. The results clearly tell the tale. I'll never use an
unpatched kernel again, not for anything approaching serious recording.
My own stress tests weren't as heavy as yours, but I did run
sample-rich mods in SoundTracker with umpteen other processes, without a
single burp, skip, or lurch. CD-spec recording with ecasound was done
under relatively "safe" conditions (no other processess running, other
than X), with absolutley no underruns.
The article will be posted to http://www.oreillynet.com later this
afternoon (Friday).
Best regards,
== Dave Phillips
http://www.bright.net/~dlphilp/index.html
http://www.bright.net/~dlphilp/linuxsound/
Paul Barton-Davis wrote:
> OK lad-folks. the news is good. i finally got to test 2.4.0-test9 with
> andrew morton's lowish latency patch. i can run ardour at 2.5msec
> latency, with a 4 way C++ compile+link, and never see a single xrun! I
> tried going to a 6 way compile, and the link step (of ardour itself)
> did cause a single xrun of 16msecs. With 5msec latency, I could not
> get things to xrun at all.
>
> This is great news. in 2.4.0-test7, I would get frequent xruns from
> memory pressure and/or intense disk activity. These have vanished. And
> this is with a set of patches that Linus looks upon fairly favorably
> (I'm not sure *how* favorably).
>
> Now, remember: this was playing back 8 tracks while both my CPU's were
> totally maxed out at 100% CPU utilization and the run queue never went
> below a value between 4 and 6. Once again, I challenge any other
> system to match this performance. Does anyone really think you could
> do a parallel build of Samplitude or Nuendo while running it at the
> same time ?
>
> OK, my hubris is running away from me here. The main message: the low
> latency sun has risen, and the summer is long.
>
> --p
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