[PATCH][AArch64] Improve Cortex-A53 FP scheduler

James Greenhalgh james.greenhalgh@arm.com
Wed Jun 14 14:21:00 GMT 2017


On Mon, Jun 12, 2017 at 02:16:44PM +0100, Wilco Dijkstra wrote:
> The Cortex-A53 scheduler model of FMAC bypass is not quite right
> for FMAC to FMAC forwarding.  Experiments also show the latencies of
> FP operations are too high as well.  Rather than adding more bypasses,
> adjust the latencies of FP instructions to get a better schedule on
> average.  As a result SPECFP2006 is 1.1% faster.

>From an AArch64 perspective this is OK, but it will need an ARM OK too,
as it is shared code.

Thanks,
James


> Passes AArch64 and ARM bootstrap and regress.
> 
> ChangeLog:
> 2017-05-30  Wilco Dijkstra  <wdijkstr@arm.com>
> 
> 	* config/arm/cortex-a53.md (cortex_a53_fpalu) Adjust latency.
> 	(cortex_a53_fconst): Likewise.
> 	(cortex_a53_fpmul): Likewise.
> 	(cortex_a53_f_load_64): Likewise.
> 	(cortex_a53_f_load_many): Likewise.
> 	(cortex_a53_advsimd_alu): Likewise.
> 	(cortex_a53_advsimd_alu_q): Likewise.
> 	(cortex_a53_advsimd_mul): Likewise.
> 	(cortex_a53_advsimd_mul_q): Likewise.
> 	(fpmac bypass): Add new bypass for fpmac-fpmac case.
> 	Add missing fmul, r2f_cvt and fconst cases.
> --



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