[gambit-list] parallel GC

James Baker james at waveformdynamics.com.au
Mon Nov 7 17:19:14 EST 2016


I just rebuilt Gambit and ran the unit tests a dozen times, which while
probably not sufficient for a solid stress test would definitely have been
enough times to demonstrate the previous behaviour and I couldn't reproduce
it.  Furthermore the timing for each run is now back down again and each
run is taking a very similar time range.

Aside from Gambit the rest of my environment has remained unchanged since I
last attempted this.

James

On Tue, Nov 8, 2016 at 8:53 AM, Marc Feeley <feeley at iro.umontreal.ca> wrote:

> Could you try again with the latest commit?  I changed the implementation
> of the barrier sync operation which is used by the GC for synchronizing
> processors.
>
> Marc
>
> > On Oct 28, 2016, at 9:09 PM, James Baker <james at waveformdynamics.com.au>
> wrote:
> >
> > I've got something else happening here on OSX (gcc 6.2.0), built with:
> v4.8.5 20161025181557 x86_64-apple-darwin16.1.0 "./configure
> '--enable-single-host' '--enable-gcc-opts' '--enable-multiple-threaded-vms'
> '--enable-activity-log' 'CC=gcc-6'"
> >
> > The unit tests complete most of the time without issue (and on occasion
> there is an additional second or so which xactlog shows as post gc wait
> time) but I've noticed a few times I can run the unit tests and they stall
> indefinitely and the percent complete is variable.  I can try and provide
> more information if its helpful.
> >
> > James
> >
> > On Sat, Oct 29, 2016 at 9:35 AM, Bradley Lucier <lucier at math.purdue.edu>
> wrote:
> > I forgot to say that this is on a machine where nproc returns 8, but
> > there's really only 4 cores and it's hyperthreaded:
> >
> > model name      : Intel(R) Xeon(R) CPU E3-1271 v3 @ 3.60GHz
> >
> > Brad
> >
> >
> > On 10/28/2016 05:54 PM, Bradley Lucier wrote:
> > > On 10/25/2016 02:41 PM, Marc Feeley wrote:
> > >> Gambit has reached a milestone today with the implementation of the
> > >> parallel garbage collector.  This is an important step towards truly
> > >> concurrent Gambit threads.
> > >>
> > >> When Gambit is configured with --enable-multiple-threaded-vms the
> > >> available processors will cooperate to do the garbage collection in
> > >> parallel.
> > >
> > > When I configure with
> > >
> > > ./configure 'CC=gcc -march=native' '--enable-single-host'
> > > '--enable-multiple-versions' '--enable-shared'
> > > --enable-multiple-threaded-vms
> > >
> > > It takes this long to run the unit tests:
> > >
> > > LD_LIBRARY_PATH=../lib:../gsi:../gsc:/usr/local/
> libimobiledevice/lib:/usr/local/Gambit/current/lib:/usr/
> local/netpbm10/lib:
> > > ../gsi/gsi -:tl,~~bin=../bin,~~lib=../lib,~~include=../include -f
> > > ./run-unit-tests.scm
> > > [ 122|   0|   0] 100% ##########################################
>  3.7s
> > > PASSED ALL 122 UNIT TESTS
> > >
> > > When I configure with
> > >
> > > heine:~/programs/gambit/gambit> ./configure 'CC=gcc -march=native'
> > > '--enable-single-host' '--enable-multiple-versions' '--enable-shared'
> > >
> > > the unit tests run in this time:
> > >
> > > LD_LIBRARY_PATH=../lib:../gsi:../gsc:/usr/local/
> libimobiledevice/lib:/usr/local/Gambit/current/lib:/usr/
> local/netpbm10/lib:
> > > ../gsi/gsi -:tl,~~bin=../bin,~~lib=../lib,~~include=../include -f
> > > ./run-unit-tests.scm
> > > [ 122|   0|   0] 100% ##########################################
>  1.6s
> > > PASSED ALL 122 UNIT TESTS
> > >
> > > That's a big difference.  This is on Ubuntu 16.10 with the built-in gcc
> > > 6.2.0.
> > >
> > > Any suggestions?
> > >
> > > Brard
> >
> > _______________________________________________
> > Gambit-list mailing list
> > Gambit-list at iro.umontreal.ca
> > https://webmail.iro.umontreal.ca/mailman/listinfo/gambit-list
> >
>
>
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