Date: Thu, 18 Nov 2010 21:30:16 +0100 From: "O. Hartmann" <ohartman@mail.zedat.fu-berlin.de> To: Lucius Windschuh <lwindschuh@googlemail.com> Cc: freebsd-performance@freebsd.org, FreeBSD Current <freebsd-current@freebsd.org>, FreeBSD Stable <freebsd-stable@freebsd.org>, Andriy Gapon <avg@freebsd.org> Subject: Re: TTY task group scheduling Message-ID: <4CE58CD8.2000407@mail.zedat.fu-berlin.de> In-Reply-To: <AANLkTimq=5KJb5AGA6H0yA7AWrp%2BHZMRhfH6pnh=_NqA@mail.gmail.com> References: <AANLkTinHSX1%2Bs3hrHyDeU2Vfp6zekTe04XkHhTc2jtLv@mail.gmail.com> <4CE50849.106@zedat.fu-berlin.de> <4CE52177.3020306@freebsd.org> <AANLkTimq=5KJb5AGA6H0yA7AWrp%2BHZMRhfH6pnh=_NqA@mail.gmail.com>
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On 11/18/10 19:55, Lucius Windschuh wrote: > 2010/11/18 Andriy Gapon<avg@freebsd.org>: >> [Grouping of processes into TTY groups] >> >> Well, I think that those improvements apply only to a very specific usage pattern >> and are greatly over-hyped. > > But there are serious issue if you use FreeBSD as a desktop OS with > SMP and SCHED_ULE, or? > Because currently, my machine is barely usable if a compile job with > parallelism is running. Movies stutter, Firefox hangs. And even nice > -n 20 doesn't do the job in every case, as +20 seems not to be the > idle priority anymore?!? > And using "idprio 1 $cmd" as a workaround is, well, a kludge. > I am not sure if TTY grouping is the right solution, if you look at > potentially CPU-intensive GUI applications that all run on the same > TTY (or no TTY at all? Same problem). > Maybe, we could simply enhance the algorithm that decides if a task is > interactive? That would also improve the described situation. > > Regards, > > Lucius Stuttering Response, being stuck for over 20 seconds also happens when I start updating the OS' sources via svn. This happens on all boxes, some of them do have 8 cores (ob two CPUs) and plenty of RAM. Heavy disk I/O, doesn't matter on UFS2 or ZFS, also brings boxes to stutter, those phenomena are most seen when you interact with the machine via X11 clients. I think it's hard to realize if a server only does console I/O, but console also seems to be stuck sometimes. It would be worth checking this with some 'benchmark'. X11 in its kind of oldish incarnation on FreeBSD seems to contribute most to those slowdowns, what so ever.
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