linux-kernel - Re: [PATCH v2 3/3] clocksource: Add clockevent support to NPS400 driver

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Date:   Thu, 10 Nov 2016 11:34:16 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Noam Camus <noamca@...lanox.com>
Cc:     "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Vineet Gupta <Vineet.Gupta1@...opsys.com>
Subject: Re: [PATCH v2 3/3] clocksource: Add clockevent support to NPS400
 driver

On 08/11/2016 09:30, Noam Camus wrote:
>> From: Daniel Lezcano [mailto:daniel.lezcano@...aro.org] 
>> Sent: Tuesday, November 1, 2016 10:02 PM
> ...
>> Assuming cpu0 and cpu1 are sibling, does
> 
>> taskset 0x1 time sleep 2 & taskset 0x2 time sleep 3
> 
> I will use 16,17 instead of 0,1
>> give a correct result without a dmesg log ?
> [root@....168.8.2 /]$ [root@....168.8.2 /]$ taskset 65536 time sleep 2 & taskset 131072 time sleep 3

Thanks for providing the numbers.

So there is no weird messages in dmesg ?

> real    0m 2.54s
> user    0m 0.04s
> sys     0m 0.14s
> real    0m 3.47s
> user    0m 0.00s
> sys     0m 0.15s
> [1]+  Done                       taskset 65536 time sleep 2
> 
> Seem OK to me.

I'm not sure of that.

2.54 instead of 2
3.47 instead of 3

0.02 time drift could be acceptable but 0.54 or 0.47 is too much.

And 0.15 in sys also a big number AFAICT.

Is the system in NO_HZ ?



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