Messages in this thread | | | Date | Wed, 27 May 2015 09:48:09 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 02/11] perf/x86: Improve HT workaround GP counter constraint |
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On Tue, May 26, 2015 at 04:33:42PM -0700, Andi Kleen wrote: > Peter Zijlstra <peterz@infradead.org> writes: > > + */ > > + if (is_ht_workaround_enabled() && !cpuc->is_fake && > > Could this function also check if at least one leaking event is > scheduled somewhere? (e.g. from a global count)
You truncated one line too many:
+ if (is_ht_workaround_enabled() && !cpuc->is_fake && + READ_ONCE(cpuc->excl_cntrs->exclusive_present)) + gpmax /= 2;
Guess what that READ_ONCE() does? It checks if there's one such leaky event on the current core.
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