[Vm-dev] Re: Nice bit trick for component add

Nicolas Cellier nicolas.cellier.aka.nice at gmail.com
Mon Dec 30 01:03:29 UTC 2013


Here is an update about performances: I compared two images that were too
much distant
(bitblt was not the only change, but there are other (Large)Integer
hacks...)

If I take two interpreter VM with only differences in BitBltPlugin
rgbAdd/alphaBlend/alphaBlendScaled, then the micro benchmark are unchanged
(-25% of run time in 32bit depth) but the text display macro benchmark is
less spectacular, only -6% of runtime.

The good news is that the macro -15% are somehow achievable by other means.

It remain to be measured in COG. My results are not reliable so far.
Here again, I have too many differences between the VM used for bench,
including recent changes from Eliot, and C compiler (LLVM 1.7 vs GCC 4.2,
from old Xcode 3.2).
I also experiment some lack of repeatability for which I did not identify
the root cause.


2013/12/30 David T. Lewis <lewis at mail.msen.com>

>
> On Fri, Dec 27, 2013 at 06:06:02PM +0100, Nicolas Cellier wrote:
> >
> > This has been capitalized at http://bugs.squeak.org/view.php?id=7802
> > I use the old squeak mantis right now rather than cog issue tracker
> > (abandonned?) or newest pharo fogbugz (restricted?)
> > What do VM maintainers prefer?
>
> Thanks for opening this issue on the mantis tracker. That happens to be
> the one that I use to try to keep track of issues that may take some time
> to resolve, and/or that require coordiation between multiple people.
>
> I have been watching #7802 with interest (though I am not a bitblt expert)
> and I will make sure that your updates get into the trunk VMM, and will
> coordinate with Eliot and/or add it to oscog directory. The trunk and
> oscog branches are pretty much identical in this area, so it's just a
> matter
> of keeping both updated, with is not a problem.
>
> >From my point of view, the bugs.squeak.org issue tracker is the one that
> I watch. I don't have an account on fogbugz, although I do read the pharo
> mailing list and try to keep up to date with issues that get mentioned
> there.
>
> The cog issue tracker was a good idea, although I think it probably got
> abandoned when people moved to fogbugz, so I do not try to keep track of
> it now.
>
> > I don't really like the balkanisation in progress, and hope we can
> converge
> > on some better communalisation again.
> >
>
> <curmudgeon alert>
>
> Inventing a new process is easy. To actually use an existing process that
> someone else invented is hard. Or so it would seem.
>
> I see the same problem in my corporate IT environments. Everybody wants
> to invent ways for the other guy to be more productive and nobody wants
> to use the other guy's ideas to actually *be* productive. I think we are
> raising a whole new generation of consultants who will all be experts on
> how the other guy should be working if only he was as smart as me :-(
>
> I should not complain because I make my living as a consultant. But still
> I dream of a world where people like me are not needed. Then I can retire
> and be happy.
>
> </curmudgeon alert>
>
> Dave
>
>
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