Messages in this thread | | | Subject | Re: [PATCH] x86: Align TLB invalidation info | From | Dave Hansen <> | Date | Wed, 31 Jan 2018 12:49:47 -0800 |
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On 01/31/2018 12:48 PM, Nadav Amit wrote: >>> On Jan 31, 2018, at 12:11 PM, Nadav Amit <namit@vmware.com> wrote: >>> >>> The TLB invalidation info is allocated on the stack, which might cause >>> it to be unaligned. Since this information may be transferred to >>> different cores for TLB shootdown, this might result in an additional >>> cache-line bouncing between the cores. >>> >>> GCC provides a way to deal with it by using >>> __builtin_alloca_with_align(). Use it to avoid the bouncing cache lines. >> Eww. How about __aligned? > Err.. Stupid me. For some reason I remembered I tried it and it didn’t have > the desired effect, which caused me to assume it does not work for variables > on the stack. Anyhow, it does the work. I’ll submit v2.
Also, just curious, but did you find this situation by inspection or did it show up in a profile somewhere?
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