Re: [Gnash-dev] IO performance

[strk]

On Fri, Jun 05, 2009 at 04:25:20PM -0600, Richard Wilbur wrote:
> On Mon, 2009-06-01 at 23:40 +0200, strk wrote:
> > Profiling of Gnash by Andrea on Amiga OS brought back
> > to my attention performance of Gnash IO operations.
> > 
> > He found out that the 100% CPU usage there is due
> > to the far too many small file reads Gnash performs.
> > 
> > This is a known issue I tried to deal with a few times
> > in the past w/out committing any big improvement yet,
> > but I'm sure there's a lot to do.
> > 
> Is there enough to keep more than one person busy? 

Yeah. I'm actually busy on other things but I'm available to
help you if you get busy here :)

> > https://savannah.gnu.org/patch/index.php?6334

> Are you interested in having someone the above-mentioned patch to apply
> to trunk or do you think there is now a better way to implement this?

I think the best help you can give is by starting to profile
parsing of big movies. If you get to the Profiling page on
wiki.gnashdev.org you should find some example ones (the aforementioned
ninja movie for instance).

Once the profiling environment is setup you may try the mmap
trick as being the easiest (less intrusive) to implement or
even just tweak the fread calls (but I dubt the caller asks for
much of that to make a big difference).

Finally, inspecting the actual users would give more hints.
IOChannel's read function is also a virtual call so chunk
reading is likely still a win here. Just I'd like to see some
numbers before chaging things.

--strk;

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