> On Feb 20, 2017, at 5:38 PM, Kyrill Tkachov <kyrylo.tkac...@foss.arm.com> > wrote: > > Hi Maxim, > > On 30/01/17 11:24, Maxim Kuvyrkov wrote: >> This patch series improves -fprefetch-loop-arrays pass through small fixes >> and tweaks, and then enables it for several AArch64 cores. >> >> My tunings were done on and for Qualcomm hardware, with results varying >> between +0.5-1.9% for SPEC2006 INT and +0.25%-1.0% for SPEC2006 FP at -O3, >> depending on hardware revision. >> >> This patch series enables restricted -fprefetch-loop-arrays at -O2, which >> also improves SPEC2006 numbers >> >> Biggest progressions are on 419.mcf and 437.leslie3d, with no serious >> regressions on other benchmarks. >> >> I'm now investigating making -fprefetch-loop-arrays more aggressive for >> Qualcomm hardware, which improves performance on most benchmarks, but also >> causes big regressions on 454.calculix and 462.libquantum. If I can fix >> these two regressions, prefetching will give another boost to AArch64. >> >> Andrew just posted similar prefetching tunings for Cavium's cores, and the >> two patches have trivial conflicts. I'll post mine as-is, since it address >> one of the comments on Andrew's review (adding a stand-alone struct for >> tuning parameters). >> >> Andrew, feel free to just copy-paste it to your patch, since it is just a >> mechanical change. >> >> All patches were bootstrapped and regtested on x86_64-linux-gnu and >> aarch64-linux-gnu. >> > > I've tried these patches out on Cortex-A72 and Cortex-A53, with the tuning > structs entries appropriately > modified to enable the changes on those cores. > I'm seeing the mcf and leslie3d improvements as well on Cortex-A72 and > Cortex-A53 and no noticeable regressions. > I've also verified that the improvements are due to the prefetch instructions > rather than just the unrolling that > the pass does. > So I'm in favor of enabling this for the cores that benefit from it. > > Do you plan to get this in for GCC 8?
Hi Kyrill, My hope was to push them in time for GCC 7, but it seems to late now. I'll return to these patches at the beginning of Stage 1. -- Maxim Kuvyrkov www.linaro.org
