From: Peter Zijlstra <firstname.lastname@example.org> To: Mark Rutland <email@example.com> Cc: firstname.lastname@example.org, Alexander Shishkin <email@example.com>, Arnaldo Carvalho de Melo <firstname.lastname@example.org>, Ingo Molnar <email@example.com>, Will Deacon <firstname.lastname@example.org> Subject: Re: [PATCH] perf: fix pmu::filter_match for SW-led groups Date: Tue, 5 Jul 2016 10:35:26 +0200 [thread overview] Message-ID: <20160705083526.GY30921@twins.programming.kicks-ass.net> (raw) In-Reply-To: <20160704180534.GD9048@leverpostej> On Mon, Jul 04, 2016 at 07:05:35PM +0100, Mark Rutland wrote: > On Sat, Jul 02, 2016 at 06:40:25PM +0200, Peter Zijlstra wrote: > > 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. > > Hmm... I'm not sure how that helps in this case. Wouldn't we still need > to walk the sibling list to get the HW PMU-id in the case of a SW group > leader? Since there is a hardware even in the group, it must be part of the hardware pmu list/tree and would thus end up classified (and sorted) by that (hardware) PMU-id. > For the heterogeenous case we'd need a different sort order per-cpu > (well, per microarchitecture), which sounds like we're going to have to > fully sort the events every time they move between CPUs. :/ Confused, I thought that for the HG case you had multiple events, one for each PMU. If we classify these events differently we'd simply use a different subtree depending on which CPU the task lands. Currently we've munged the two PMUs together, because, well, that's the only way. > I also had another though about solving the SW-led group case: if the > leader had a reference to the group's HW PMU (of which there should only > be one), we can filter on that alone, and can also use that in > group_sched_in rather than the ctx->pmu, avoiding the issue that > ctx->pmu is not the same as the group's HW PMU. > > I'll have a play with that approach in the mean time. Right, adds one more pointer to the struct event, but that thing is massive already.
next prev parent reply other threads:[~2016-07-05 8:35 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 2016-07-04 18:05 ` Mark Rutland 2016-07-05 8:35 ` Peter Zijlstra [this message] 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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