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From: Peter Zijlstra <peterz@infradead.org>
To: Song Liu <songliubraving@fb.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>,
	Ingo Molnar <mingo@kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	"acme@kernel.org" <acme@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>,
	Stephane Eranian <eranian@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"mark.rutland@arm.com" <mark.rutland@arm.com>,
	"megha.dey@intel.com" <megha.dey@intel.com>,
	"frederic@kernel.org" <frederic@kernel.org>
Subject: Re: [RFC][PATCH] perf: Rewrite core context handling
Date: Wed, 17 Oct 2018 13:06:51 +0200	[thread overview]
Message-ID: <20181017110651.GI3121@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <FE66AE20-9785-4CF7-8D8D-CF2A9C696923@fb.com>

On Tue, Oct 16, 2018 at 06:28:10PM +0000, Song Liu wrote:
> > How about this: 
> > 
> > 1. Keep multiple perf_cpu_context per CPU, just like before this patch. 
> > 
> > 2. For perf_event_context, add PMU as an order for the RB tree. 
> > 
> > 3. (hw) pmu->perf_cpu_context->ctx only has events for this PMU (and sw 
> >   events moved to this context).
> > 
> > 4. task->perf_event_ctxp has events for all PMUs. 
> > 
> > With this path, we keep the existing perf_cpu_context/perf_event_context
> > logic as-is, which I think is simp\x10ler than the new logic (with extra
> > *_pmu_context). And it should also solve the problem. 
> > 
> > Does this make sense? If this doesn't look too broken, I am happy to
> > draft RFC for it. 
> > 
> 
> I am not sure whether you missed this one, or found it totally insane. 
> Could you please share your comments on it? My gut feeling is that this 
> would be a simpler patch to solve the problem (two hw PMUs). (It might 
> be less efficient though). 

Ah, sorry, somehow this email got lost.

That makes task and cpu contexts wildly different, which will complicate
matters I feel.


  reply	other threads:[~2018-10-17 11:07 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-10 10:45 [RFC][PATCH] perf: Rewrite core context handling Peter Zijlstra
2018-10-11  7:50 ` Song Liu
2018-10-11  9:29   ` Peter Zijlstra
2018-10-11 22:37     ` Song Liu
2018-10-12  9:50       ` Peter Zijlstra
2018-10-12 14:25         ` Peter Zijlstra
2018-10-13  8:31         ` Song Liu
2018-10-16  9:50           ` Peter Zijlstra
2018-10-16 16:34             ` Song Liu
2018-10-16 18:10               ` Peter Zijlstra
2018-10-16 18:24                 ` Song Liu
2018-10-12  7:04     ` Alexey Budankov
2018-10-12 11:54       ` Peter Zijlstra
2018-10-15  7:26 ` Alexey Budankov
2018-10-15  8:34   ` Peter Zijlstra
2018-10-15  8:53     ` Peter Zijlstra
2018-10-15 17:29     ` Alexey Budankov
2018-10-15 18:31       ` Stephane Eranian
2018-10-16  6:39         ` Alexey Budankov
2018-10-16  9:32         ` Peter Zijlstra
2018-10-15 22:09     ` Song Liu
2018-10-16 18:28       ` Song Liu
2018-10-17 11:06         ` Peter Zijlstra [this message]
2018-10-17 16:43           ` Song Liu
2018-10-17 17:19             ` Peter Zijlstra
2018-10-17 18:33               ` Peter Zijlstra
2018-10-17 18:57                 ` Song Liu
2018-10-16 16:26 ` Mark Rutland
2018-10-16 18:07   ` Peter Zijlstra
2018-10-17  8:57 ` Alexey Budankov
2018-10-17 15:01   ` Alexander Shishkin
2018-10-17 15:58     ` Alexey Budankov
2018-10-17 16:30   ` Peter Zijlstra
2018-10-18  7:05     ` Alexey Budankov
2018-10-22 13:26 ` Alexander Shishkin
2018-10-23  6:13 ` Song Liu
2018-10-23  6:55   ` Peter Zijlstra
2019-05-15 11:17 ` Alexander Shishkin

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