From: Peter Zijlstra <email@example.com> To: Mark Rutland <firstname.lastname@example.org> Cc: email@example.com, Alexander Shishkin <firstname.lastname@example.org>, Arnaldo Carvalho de Melo <email@example.com>, Ingo Molnar <firstname.lastname@example.org>, Will Deacon <email@example.com> Subject: Re: [PATCH] perf: fix pmu::filter_match for SW-led groups Date: Sat, 2 Jul 2016 18:40:25 +0200 [thread overview] Message-ID: <20160702164025.GU30921@twins.programming.kicks-ass.net> (raw) In-Reply-To: <firstname.lastname@example.org> On Tue, Jun 14, 2016 at 04:10:41PM +0100, Mark Rutland wrote: > However, pmu::filter_match is only called for the leader of each event > group. When the leader is a SW event, we do not filter the groups, and > may fail at pmu::add time, and when this happens we'll give up on > scheduling any event groups later in the list until they are rotated > ahead of the failing group. Ha! indeed. > I've tried to find a better way of handling this (without needing to walk the > siblings list), but so far I'm at a loss. At least it's "only" O(n) in the size > of the sibling list we were going to walk anyway. > > I suspect that at a more fundamental level, I need to stop sharing a > perf_hw_context between HW PMUs (i.e. replace task_struct::perf_event_ctxp with > something that can handle multiple HW PMUs). From previous attempts I'm not > sure if that's going to be possible. > > Any ideas appreciated! So I think I have half-cooked ideas. One of the problems I've been wanting to solve for a long time is that the per-cpu flexible list has priority over the per-task flexible list. I would like them to rotate together. One of the ways I was looking at getting that done is a virtual runtime scheduler (just like cfs). The tricky point is merging two virtual runtime trees. But I think that should be doable if we sort the trees on lag. In any case, the relevance to your question is that once we have a tree, we can play games with order; that is, if we first order on PMU-id and only second on lag, we get whole subtree clusters specific for a PMU. Lost of details missing in that picture, but I think something along those lines might get us what we want.
next prev parent reply other threads:[~2016-07-02 16:40 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-06-14 15:10 Mark Rutland 2016-07-02 16:40 ` Peter Zijlstra [this message] 2016-07-04 18:05 ` Mark Rutland 2016-07-05 8:35 ` Peter Zijlstra 2016-07-05 9:44 ` Mark Rutland 2016-07-05 12:04 ` Peter Zijlstra 2016-07-05 12:52 ` Mark Rutland 2016-07-07 8:31 ` [tip:perf/core] perf/core: Fix " tip-bot for Mark Rutland
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