linux-kernel - Re: [regression] cross core scheduling frequency drop bisected to 0c313cb20732

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Message-ID: <1460186846.3765.168.camel@gmail.com>
Date:	Sat, 09 Apr 2016 09:27:26 +0200
From:	Mike Galbraith <umgwanakikbuti@...il.com>
To:	Doug Smythies <dsmythies@...us.net>
Cc:	'Peter Zijlstra' <peterz@...radead.org>,
	"'Rafael J. Wysocki'" <rafael.j.wysocki@...el.com>,
	'LKML' <linux-kernel@...r.kernel.org>,
	'Linux PM list' <linux-pm@...r.kernel.org>,
	'Rik van Riel' <riel@...hat.com>,
	"'Rafael J. Wysocki'" <rjw@...ysocki.net>
Subject: Re: [regression] cross core scheduling frequency drop bisected to
 0c313cb20732

On Sat, 2016-04-09 at 00:17 -0700, Doug Smythies wrote:

> I still didn't find the exact same program, but I think I found some
> earlier version of the correct test.
> 
> I get (long term average):
> Kernel 4.4.0-17: Powersave 3.93 usecs/loop ; Performance 3.93 usecs/loop 0.89
> Kernel 4.5-rc7: Powersave 3.47 usecs/loop ; Performance 3.51 usecs/loop  1.00
> Kernel 4.6-rc1: Powersave 3.84 usecs/loop ; Performance 3.88 usecs/loop  0.90
> 
> So, similar results (so far, I didn't try reverted yet).

I likely see a bit more go missing because I throttle no_hz when idle
is being hammered at high frequency.

	-Mike