RFR 8134802 - LCM register pressure scheduling
Vladimir Kozlov
vladimir.kozlov at oracle.com
Sat Sep 12 13:59:40 UTC 2015
Main motivation for this work is reduce spills. Spill instructions could
be still expensive even if a processor has good OOO execution.
We want to start on one platform first to find all problems before
moving to others.
Thanks,
Vladimir
On 9/12/15 2:37 AM, Andrew Haley wrote:
> On 09/12/2015 04:58 AM, Vladimir Kozlov wrote:
>> I looked on performance data and for scimark.lu.large C2 time increase
>> significantly (~ 39%) while score did not improve (0,18%).
>> I can accept compilation time regression if it gives performance
>> improvement as crypto.aes. But otherwise we need to investigate why that
>> happens.
>
> Is there any intention to look at other processors? x86-64 tends to
> be very aggressively out-of-order, which reduces the need for
> scheduling to reduce the effects of latency. Of course I'm interested
> in AArch64, but it has more registers so tends to spill less; perhaps
> ARM-32 would be an interesting candidate.
>
> Andrew.
>
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