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From: Ian Rogers <irogers@google.com>
To: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>, Kajol Jain <kjain@linux.ibm.com>,
	John Garry <john.garry@huawei.com>,
	Jin Yao <yao.jin@linux.intel.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Kim Phillips <kim.phillips@amd.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	linux-perf-users <linux-perf-users@vger.kernel.org>,
	Vince Weaver <vincent.weaver@maine.edu>,
	Stephane Eranian <eranian@google.com>
Subject: Re: [RFC PATCH v3 12/14] perf metricgroup: order event groups by size
Date: Wed, 20 May 2020 00:46:22 -0700	[thread overview]
Message-ID: <CAP-5=fVPh0og6CmjM4G1bDGB_S+Sp4v_4WM3r5XqwQPbk7ASdg@mail.gmail.com> (raw)
In-Reply-To: <20200509024019.GI3538@tassilo.jf.intel.com>

On Fri, May 8, 2020 at 7:40 PM Andi Kleen <ak@linux.intel.com> wrote:
>
> > > I'm not sure if size is that great an heuristic. The dedup algorithm should
> > > work in any case even if you don't order by size, right?
> >
> > Consider two metrics:
> >  - metric 1 with events {A,B}
> >  - metric 2 with events {A,B,C,D}
> > If the list isn't sorted then as the matching takes the first group
> > with all the events, metric 1 will match {A,B} and metric 2 {A,B,C,D}.
> > If the order is sorted to {A,B,C,D},{A,B} then metric 1 matches within
> > the {A,B,C,D} group as does metric 2. The events in metric 1 aren't
> > used and are removed.
>
> Ok. It's better for the longer metric if they stay together.
>
> >
> > The dedup algorithm is very naive :-)
>
> I guess what matters is that it gives reasonable results on the current
> metrics. I assume it does?
>
> How much deduping is happening if you run all metrics?

Hi Andi,

I included this data in the latest cover-letter:
https://lore.kernel.org/lkml/20200520072814.128267-1-irogers@google.com/

> For toplev on my long term todo list was to compare it against
> a hopefully better schedule generated by or-tools, but I never
> got around to coding that up.
>
> -Andi

Agreed, and this relates to your comments about doing the algorithm as
a separate pass outside of find_evsel_group. For that, I don't
disagree but would like to land what we have and then follow up with
improvements.

Thanks,
Ian

  reply	other threads:[~2020-05-20  7:46 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-08  5:36 [RFC PATCH v3 00/14] Share events between metrics Ian Rogers
2020-05-08  5:36 ` [RFC PATCH v3 01/14] perf parse-events: expand add PMU error/verbose messages Ian Rogers
2020-05-09  0:14   ` Andi Kleen
2020-05-08  5:36 ` [RFC PATCH v3 02/14] perf test: improve pmu event metric testing Ian Rogers
2020-05-08  5:36 ` [RFC PATCH v3 03/14] lib/bpf hashmap: increase portability Ian Rogers
2020-05-08  5:36 ` [RFC PATCH v3 04/14] libbpf: Fix memory leak and possible double-free in hashmap__clear Ian Rogers
2020-05-08  5:36 ` [RFC PATCH v3 05/14] perf expr: fix memory leaks in bison Ian Rogers
2020-05-08  5:36 ` [RFC PATCH v3 06/14] perf evsel: fix 2 memory leaks Ian Rogers
2020-05-09  0:39   ` Andi Kleen
2020-05-09  0:41     ` Ian Rogers
2020-05-08  5:36 ` [RFC PATCH v3 07/14] perf expr: migrate expr ids table to libbpf's hashmap Ian Rogers
2020-05-08  5:36 ` [RFC PATCH v3 08/14] perf metricgroup: change evlist_used to a bitmap Ian Rogers
2020-05-08  5:36 ` [RFC PATCH v3 09/14] perf metricgroup: free metric_events on error Ian Rogers
2020-05-21 17:07   ` Arnaldo Carvalho de Melo
2020-05-08  5:36 ` [RFC PATCH v3 10/14] perf metricgroup: always place duration_time last Ian Rogers
2020-05-08  5:36 ` [RFC PATCH v3 11/14] perf metricgroup: delay events string creation Ian Rogers
2020-05-08  5:36 ` [RFC PATCH v3 12/14] perf metricgroup: order event groups by size Ian Rogers
2020-05-09  0:25   ` Andi Kleen
2020-05-09  0:40     ` Ian Rogers
2020-05-09  2:40       ` Andi Kleen
2020-05-20  7:46         ` Ian Rogers [this message]
2020-05-08  5:36 ` [RFC PATCH v3 13/14] perf metricgroup: remove duped metric group events Ian Rogers
2020-05-09  0:38   ` Andi Kleen
2020-05-08  5:36 ` [RFC PATCH v3 14/14] perf metricgroup: add options to not group or merge Ian Rogers
2020-05-09  0:12 ` [RFC PATCH v3 00/14] Share events between metrics Andi Kleen

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