Date: Wed, 6 Jul 2005 14:55:31 -0400 From: Kris Kennaway <kris@obsecurity.org> To: freebsd-questions@freebsd.org Cc: "Scott I. Remick" <scott@sremick.net> Subject: Re: Weird "nice" behavior Message-ID: <20050706185531.GA31552@xor.obsecurity.org> In-Reply-To: <44u0j7iyep.fsf@be-well.ilk.org> References: <pan.2005.07.06.03.56.44.535357@sremick.net> <44u0j7iyep.fsf@be-well.ilk.org>
next in thread | previous in thread | raw e-mail | index | archive | help
--9jxsPFA5p3P2qPhR
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable
On Wed, Jul 06, 2005 at 02:26:22PM -0400, Lowell Gilbert wrote:
> "Scott I. Remick" <scott@sremick.net> writes:
>=20
> > I'm seeing something strange/annoying tonight... maybe someone could he=
lp
> > explain why it's happening.
> >=20
> > FreeBSD 5.4-RELEASE
> >=20
> > I'm trying to do a large local rsync in the background, while listening=
to
> > streaming audio via RealPlayer and do other stuff. I have the rsync
> > running at nice level 20 ("nice -20") which I've confirmed via ps:
> >=20
> > 1001 77010 1452 0 116 20 45056 44332 select SN+ p1 0:30.89 rsyn=
c -av -=20
> > 1001 77011 77010 295 139 20 45048 44232 - RN+ p1 20:17.12 rsyn=
c -av -=20
> > 1001 77548 77011 0 116 20 45200 44460 select SN+ p1 0:12.06 rsyn=
c -av -
> >=20
> > RealPlayer is running at normal nice (0):
> > 1001 80675 80650 16 98 0 30004 12516 select S p2 0:22.69 /usr=
/local/lib/RealPlayer/realplay.bin
> > 1001 80688 80675 0 96 0 30004 12516 select S p2 0:00.01 /usr=
/local/lib/RealPlayer/realplay.bin
> > 1001 80689 80688 0 20 0 30004 12516 pause S p2 0:02.67 /usr=
/local/lib/RealPlayer/realplay.bin
> > 1001 80692 80675 24 -8 0 13844 6772 piperd I p2 0:00.00 /usr=
/local/lib/RealPlayer/realplay.bin
> > 1001 80693 80675 24 -8 0 13844 6772 piperd I p2 0:00.00 /usr=
/local/lib/RealPlayer/realplay.bin
> > 1001 80694 80688 24 20 0 30004 12516 pause I p2 0:00.00 /usr=
/local/lib/RealPlayer/realplay.bin
> > 1001 80695 80688 0 20 0 30004 12516 pause S p2 0:01.34 /usr=
/local/lib/RealPlayer/realplay.bin
> > 1001 80696 80688 0 8 0 30004 12516 nanslp S p2 0:01.13 /usr=
/local/lib/RealPlayer/realplay.bin
> > 1001 80765 80688 0 8 0 30004 12516 nanslp S p2 0:01.10 /usr=
/local/lib/RealPlayer/realplay.bin
> >=20
> > Not sure why it spawns so many processes, but whatever...
> >=20
> > Anyway, what's happening is despite rsync being nice 20, RealPlayer is
> > incredibly choppy. Even if I'm not doing anything else on the system.=
=20
> >=20
> > Now here's the weirder part: if I DO do something, such as just scrolli=
ng
> > a window, the audio stream stops being choppy. It's as if it takes some
> > OTHER application claiming CPU cycles to get rsync to properly play "ni=
ce"
> > and release up time, at which point RealPlayer gets the cycles it
> > deserves. But for some reason, rsync with just RealPlayer on its own wi=
ll
> > not play "nice" and give up time to RealPlayer like it should since
> > RealPlayer is running at 0 and rsync is running at 20.
>=20
> Sounds like you're blocked on I/O, not CPU. =20
> SCSI drives with tagged queueing would probably perform better.
Also look for Jeff Roberson's patch that addresses this performance
problem, which was sent (and committed) to -current a month or so ago,
and which I think I forwarded to -stable.
Kris
--9jxsPFA5p3P2qPhR
Content-Type: application/pgp-signature
Content-Disposition: inline
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.1 (FreeBSD)
iD8DBQFCzCkiWry0BWjoQKURAgRjAKCQd9BAipljfqzE/cSFt19JxkksbACg45Ag
WLABeOijaKomZwtsErCBGMc=
=I0qZ
-----END PGP SIGNATURE-----
--9jxsPFA5p3P2qPhR--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20050706185531.GA31552>