Re[4]: [Gc] Boehm GC and Iphone

Ivan Maidanski ivmai at mail.ru
Thu Jan 13 13:26:06 PST 2011


Hi,

If the platform is not multi-core then parallel-mark mode should be off (either at compile time or at runtime).
But turning on generation mode could reduce the GC pause on a single-core.

Regards.

Thu, 13 Jan 2011 08:28:55 -0300 Damian <damian.pop at gmail.com>:
> None is multicore. Will I get an inprovement anyway?
> Ok, I will try to compile gc7.2 BDWGC snapshot tonight.
> Thanks!
> 
> 2011/1/13 Ivan Maidanski <ivmai at mail.ru>
> 
> > Hi,
> >
> > 1. Are you going to run it on a multi-core? (I don't know Apples devices
> > internals deeply, so I wonder which of them have multi-core CPUs).
> >
> > 2. If you start using gc6.8 just because of the reason you mentioned, I
> > recommend you to migrate to gc7.2 (get the recent BDWGC snapshot which now
> > has generation plus parallel collection enabled).
> >
> > 3. Incremental/generation collection as well as parallel marking are the GC
> > improvements aiming collection pause reduction.
> >
> > Regards.
> >
> > Wed, 12 Jan 2011 20:03:02 -0300 Damian <damian.pop at gmail.com>:
> >
> > > Maybe concurrent + parallel collection does not what I'm expecting.
> > > What I need to achieve is to reduce the collection pause.
> > > I'm using version 6.8 (because I've found somewhere on the internet
> > someone
> > > has made it work on iphone with some changes) and I'm having collection
> > > cycles of about 120ms. I need to reduce that number. I don't care if
> > overall
> > > collection time increases as long as the app is not freezed for such a
> > long
> > > time.
> > > Is that possible?
> > >
> > > Thanks.
> > >
> > > 2011/1/12 Ivan Maidanski <ivmai at mail.ru>
> > >
> > > > Hi,
> > > >
> > > > BTW What Apple devices has a multi-core CPU at present?
> > > >
> > > > I ran GC test on a single-core with GC_MARKERS=4 - collector appears to
> > > > work...
> > > >
> > > > Wed, 12 Jan 2011 10:04:00 -0300 Damian <damian.pop at gmail.com>:
> > > >
> > > > > Hi,
> > > > > Is it possible to compile boehm gc for iphone enabling generational
> > and
> > > > parallel collection?
> > > >
> > > > See the recent post by Hans.
> > > >
> > > > I try to enable generational collection on multi-cores (regardless
> > whether
> > > > this slows down the GC in average or not - anyway it is not on by
> > default).
> > > > FYI: At present, generational collection on multi-cores enabled only on
> > > > Win32.
> > > >
> > > > Regards.
> > > >
> > > > > I will try to do so; probably I will need help, but for now al least
> > I
> > > > want to know it it's possible at all.
> > > > > Thanks
> >
> >



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