linux-kernel - Re: [PATCH] clocksource: Allow toggling between runtime and persistent clocksource for idle

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 6 Jul 2015 10:51:05 -0700
From:	John Stultz <john.stultz@...aro.org>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Tony Lindgren <tony@...mide.com>,
	lkml <linux-kernel@...r.kernel.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	Felipe Balbi <balbi@...com>, Nishanth Menon <nm@...com>,
	Yingjoe Chen <yingjoe.chen@...iatek.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH] clocksource: Allow toggling between runtime and
 persistent clocksource for idle

On Mon, Jul 6, 2015 at 8:46 AM, Thomas Gleixner <tglx@...utronix.de> wrote:
> On Mon, 6 Jul 2015, Tony Lindgren wrote:
>> * Thomas Gleixner <tglx@...utronix.de> [150706 07:20]:
>> > On Mon, 6 Jul 2015, Tony Lindgren wrote:
>> The timekeeping accuracy issue certainly needs some thinking, and
>> also the resolution between the clocksources can be different.. In the
>> test case I have the slow timer is always on and of a lower resolution
>> than the ARM global timer being used during runtime.
>>
>> Got some handy timer test in mind you want me to run to provide data
>> on the accuracy?
>
> John Stultz might have something.

You can turn on ntp stats in your ntp.conf and chart the loopstats
data w/ gnuplot:

set terminal png
set output "loopstat.png"
plot "/var/log/ntpstats/loopstats.<dateoftest>" using 2:3 with linespoints


I also have  the drift-log.py and graph-log.py scripts I use here:
https://github.com/johnstultz-work/timetests

But those aren't really ready for mass consumption, as they're
probably not very cross-distro compatible.

thanks
-john
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/