Re: [LAU] Sanity check needed: Fons's Auto Wah on 64-bit system and CPU usage?

Excerpts from Ken Restivo's message of Thu Jan 14 02:38:04 +0100 2010:
> I've been running Fons's great Auto-Wah on my 32-bit Netbook for many months
> now, using it live constantly, and I love it.
>
> I'm going into the studio Friday, so I've dusted off my 64-bit Core 2 Duo
> system and putting it through its paces.
>
> Turns out that on my Core2Duo, JACK RACK running Fons's auto-wah plugin sucks
> up 6% CPU even if there is no sound going through it.
>
> I asked Fons about it; he can't duplicate the problem since he doesn't have a
> 64-bit system. Hell, I can't even duplicate it on my 32-bit system; it's 64-bit
> dependent.
>
> I looked at the output with Bitmeter at Fons' suggestion, and it seems there
> are no denormals, inf's, or nans-- just a very small -230dB DC offset in the
> code (probably to avoid denormals).
>
> The CPU usage ramps up before any signal is fed into the plugin. It runs
> normally when there is signal, but then it keeps sucking up CPU afterwards. I'm
> feeding it from fluidsynth, and bitmeter says that it isn't sending anthing at
> all during silent moments.
>
> It doesn't run away to 99% CPU (or 50% on a Core2Duo), like it would if there
> were a denormal. But still, why is it using up CPU when there's no signal? That
> seems odd. And why only on my 64-bit machine? FWIW, the 64-bit and 32-bit
> machines I have are even running the same kernel and RT-patch versions
> (2.6.26.8-rt12).
>
> Can someone with a 64-bit system help me by trying to duplicate the problem?
> I'm looking to see if JACK-RACK running just Fons' plugin uses as much CPU with
> silence as when there's signal running through it.
>
> Oh, and in case it's setting-dependent, here is the rack with the settings I'm
> using:
>
> http://restivo.org/misc/clavy-phaser.rack
>
> -ken

Hi Ken.
I'm on 64 bit, so I thought I give it a shot, however, my 64 bit system
is a bit unusual since it's only a single core celeron.

The result is vastly different from yours, cpu usage of jack-rack in
htop is 0.0% most of the time, occasionally it shows 1.0%, so not even
when running it shows the 6% you get.
I only give it some webradio from mplayer, and it doesn't seem to matter
whether it's playing or not or whether it's connected, it's all the
same. I was clever enough to enable the plugin in jack-rack.

What I do get around 6% is mem usage (out of 1GB).

Hope that helps.
Regards,
Philipp

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Received on Thu Jan 14 16:15:02 2010