Messages in this thread | | | Subject | Re: [PATCH v4 3/3] mm/free_pcppages_bulk: prefetch buddy while not holding lock | From | Vlastimil Babka <> | Date | Fri, 2 Mar 2018 19:08:00 +0100 |
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On 03/02/2018 07:00 PM, Dave Hansen wrote: > On 03/02/2018 09:55 AM, Vlastimil Babka wrote: >> It's even stranger to me. Struct page is 64 bytes these days, exactly a >> a cache line. Unless that changed, Intel CPUs prefetched a "buddy" cache >> line (that forms an aligned 128 bytes block with the one we touch). > > I believe that was a behavior that was specific to the Pentium 4 > "Netburst" era. I don't think the 128-byte line behavior exists on > modern Intel cpus.
I remember it on Core 2 something (Nehalem IIRC). And this page suggests up to Broadwell, and it can be disabled. And it's an L2 prefetcher indeed. https://software.intel.com/en-us/articles/disclosure-of-hw-prefetcher-control-on-some-intel-processors
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