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Date:      Thu, 11 Dec 2003 11:42:42 +0200
From:      Ian Freislich <ianf@za.uu.net>
To:        Mathew Kanner <mat@cnd.mcgill.ca>
Cc:        freebsd-current@freebsd.org
Subject:   Re: Why are sound ioctl calls so slow? 
Message-ID:  <67589.1071135762@za.uu.net>
In-Reply-To: Your message of "Wed, 10 Dec 2003 11:49:57 EST." <20031210164957.GJ11072@cnd.mcgill.ca> 
References:  <20031210164957.GJ11072@cnd.mcgill.ca> 

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Mathew Kanner wrote:
> On Dec 10, Ian Freislich wrote:
> > Mathew Kanner wrote:
> > > 	My first guess would be the device is rebuilding feeder/mixer
> > > chains every time mpg123 changes format.  I would run the test one
> > > more time, disabling vchans and rate conversion.
> > > 
> > > 	sysctl hw.snd.report_soft_formats=0 hw.snd.maxautovchans=0
> > 
> > That didn't make a (noticeable) difference:
> > 
> >   4090 mpg123   0.000603 CALL  ioctl(0x3,SNDCTL_DSP_STEREO,0xbfbff864)
> >   4090 mpg123   0.026047 RET   ioctl 0
> >   4090 mpg123   0.000582 CALL  ioctl(0x3,SNDCTL_DSP_SPEED,0xbfbff864)
> >   4090 mpg123   0.017735 RET   ioctl 0
> >   4090 mpg123   0.000414 CALL  ioctl(0x3,SNDCTL_DSP_SETFMT,0xbfbff864)
> >   4090 mpg123   0.026004 RET   ioctl 0
> 
> 	You complained that mpg123 was doing hundered of system calls.
> Did that remain constant aswell?

Yes it it did.

Ian



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