allocation prefetching with block initializing instructions

Doerr, Martin martin.doerr at
Tue Aug 16 03:31:53 PDT 2011

Hello everybody,

I have read your emails about the allocation prefetching on SPARC.
Avoiding fetching the cache lines from memory seems to make a lot of sense.
However, it should be possible to use these block initializing stores to replace
the ClearArray nodes in addition. We are loosing quite some time in these
clear loops.

Have you guys already thought about this?

I had played with the ZeroTLAB switch some time ago, but the TLABs appear to
get too large so clearing them at once doesn't perform well. But if we only
clear to something like a prefetch watermark and get rid of the ClearArray
we should get better performance. We only have to make sure that we always clear
up to some distance behind the object being allocated.

I'm looking forward to read your comments. Kind regards,
Martin D

-------------- next part --------------
An HTML attachment was scrubbed...

More information about the hotspot-compiler-dev mailing list