Regarding knl hardware prefetcher, I read something like “hardware prefetchers can be disabled within the BIOS menus at boot time or using BIOS tools, specific to your machine”.
I am not sure if this is true (for current knl nodes / BIOS), people who can look at BIOS settings or intel folks can provide more information regarding this.
“software” or “compiler” prefetching is enabled by default with -O2 which could be disabled by -opt-prefetch=0 / -no-opt-prefetch or “pragma noprefetch”.
I see prefetch instructions like prefetcht0, prefetchnt1 or _mm_prefetch intrinsics but haven’t come across anything to disable it like data stream control register you mentioned for power8 (expect for
some other
microarchitectures).
-Pramod
Last time i asked intel it was not possible to disable hardware prefetcher. I believe you can pass hints to indicate you want to disable software prefetcher but i dont remember whether they were just hints (that can be ignored) or not.
Best,
Fabien
Hi,
Is there a way to disable HW prefetch on KNL? For ex, on POWER8, user can use intrinsics such as __prefetch_set_dscr_register(40) to disable hw prefetch Or user can use a compiler flag to control prefetch. Is there a similar
method available for KNL?
regards
Sudheer
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