RFR: 8227226: Segmented array clearing for ZGC

[Andrew Haley]

On 7/26/19 6:56 PM, Erik Osterlund wrote:

> I like the direction of [clearing pages when they are reclaimed], as
> I think it will help us down the road.

Are you sure this will help? If the cache lines for a page are already
in exclusive state (i.e. they've been written) when reclaimed this
will be fine, otherwise you're generating extra cache coherence
traffic. You're also evicting the cache of the GC thread by filling it
with zeroed lines.

I guess some careful benchmarking will tell us.

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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