This is something I am interested in doing as well. I had corresponded with
Julian Eischen & Daniel Elischer about this.
This was suggested by them but I haven't been able to figure it
all out. Basically we could create SYSTEM_SCOPE pthreads. This way
there is one KSE per pthread. I was hoping I could bind each KSE
using sched_bind() - however the kernel doesn't handle this very
well.
I know this sort of thing isn't for every one but it can be useful as John G.
has indicated.
Will the gurus here comment on whether this approach will work and what I am
doing wrong.
Mucho Gracias,
Peter
List: freebsd-hackers Subject: pin/bind a pthread to a processor?
(take 2) From: John Giacomoni <John.Giacomoni () colorado ! edu> Date:
2007-01-30 23:34:28 Message-ID: 722B66D4-4030-4C12-8C8D-8B3288F86498 ()
colorado ! edu
Previously when I asked this question it turned out to not be as necessary as
I thought. However, I now need a way to pin/bind a user-space thread to a
processor until I'm done with it as my timing constraints are too tight to
account for. I checked sys/sched.h, sys/proc.h, pthread.h, and pthread_np.h
but it doesn't look like an API to do this was added in 6.2. Can someone
point me at a way to hack this in? I'm working on a conference submission and
I unfortunately need to pin in user-space as abusing non-preemptive kernel
threads is not sufficient for my task. The plan is to have 1-3 threads
pinned through the execution of the test (30s - 10min, maybe more) but to
leave a cpu untouched so that normal system function can continue on it.
When pinning I'd also like to be able to pin to specific processors so I
account for the effects placement of different dies, important for my work on
dual-processor dual-core AMD systems where IO is routed via
hypertransport through the first processor. For those who are
interested, this work is focused on building pipeline-parallel systems that
overlap sequential work by streaming data through a sequence of processors.
One app that I've built with it is to support GigE forwarding at the maximum
rate for all frame sizes through user-space. When this work is complete it
may be able to help Daniel O'Connor and his question about streaming data from
the kernel to userland (1/18/07). Additional information and papers are
available at http://www.cs.colorado.edu/~jgiacomo thanks for any help!
John G On Sep 8, 2006, at 6:33 PM, David Xu wrote: > On Saturday 09
September 2006 04:18, John Giacomoni wrote: >> Is it possible to bind a
pthread to a processor in 5.5 or 6.1? >> >> I currently have a code base that
uses libpthread with multiple >> threads, mutexes and condition variables. >>
The problem I'm having is that I seem to be suffering wall-clock
>> timing aberrations that I believe are introduced by the scheduler. >> >>
>> Thanks, >> >> John G >> >> -- >> >> [EMAIL PROTECTED] >> University
>> of Colorado at Boulder >> Department of Computer Science >> Engineering
>> Center, ECCR 1B50 >> 430 UCB >> Boulder, CO 80303-0430 >> USA > > I
>> don't think we have such API allowing you to bind a thread to > a specific
>> CPU, I had implemented such an API for DragonFlyBSD, but > its 1:1
>> threading is not mature yet. > > David Xu >
>> _______________________________________________ >
>> [email protected] mailing list >
>> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To
>> unsubscribe, send any mail to "freebsd-hackers- > [EMAIL PROTECTED]"
>> -- [EMAIL PROTECTED] University of Colorado at Boulder Department of
>> Computer Science Engineering Center, ECCR 1B50 430 UCB Boulder, CO
>> 80303-0430 USA
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