> Hi Diego,
>
> Thanks for the summary, it's great to see the progress of the project.  Do
> you have any compile time numbers for LTO so far?  If you pick a mid-sided
> program from spec or even a bootstrap, how much slower is LTO than compiling
> at -O3?

We haven't tried a bootstrap with LTO enabled yet (needs some changes
to the build system to find the gold plugin during bootstrap). We
should probably try -flto-single one day...

Some initial testing with internal apps showed that the streamer is
normally a problem and in some cases the performance is IO bound! This
is very true if the streamer debug is enabled, since that adds some
fairly large synchronization strings to the output.

Cary wrote a patch to gold to ignore IL sections if not using the
plugin, and it had a noticeable impact..

Diego, you tested SPEC a bit, do you know what the slowdown was?

> -Chris
>


Cheers,
-- 
Rafael Avila de Espindola

Google | Gordon House | Barrow Street | Dublin 4 | Ireland
Registered in Dublin, Ireland | Registration Number: 368047

Reply via email to