linux-kernel - RE: [PATCH 2/2][RFC] tools/power turbostat: Introduce reliable RAPL display

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Message-ID: <36DF59CE26D8EE47B0655C516E9CE6405F3966F2@SHSMSX103.ccr.corp.intel.com>
Date:   Fri, 14 Aug 2020 14:34:01 +0000
From:   "Chen, Yu C" <yu.c.chen@...el.com>
To:     Len Brown <lenb@...nel.org>
CC:     Linux PM list <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Zhang, Rui" <rui.zhang@...el.com>
Subject: RE: [PATCH 2/2][RFC] tools/power turbostat: Introduce reliable RAPL
 display

Hi Len,
> From: Len Brown <lenb@...nel.org>
> Sent: Friday, August 14, 2020 5:51 AM
> To: Chen, Yu C <yu.c.chen@...el.com>
> Cc: Linux PM list <linux-pm@...r.kernel.org>; Linux Kernel Mailing List <linux-
> kernel@...r.kernel.org>; Zhang, Rui <rui.zhang@...el.com>
> Subject: Re: [PATCH 2/2][RFC] tools/power turbostat: Introduce reliable RAPL
> display
> 
> why not simply use nanosleep(2)
> 
> 
Do you mean, use nanosleep rather than the timer to accumulate the RAPL data?
After thinking for a while, it looks like if we use nanosleep we might
 need to create a new thread within the turbostat  and sleep every few seconds
 (according to the RAPL register timeout) to accumulate the running RAPL. And might
need to deal with some race conditions between new thread and the main turbostat
thread. But yes, it can be switched to nanosleep() to check if the code would look
simpler.

BTW, we have a v3 of the patch at
https://lore.kernel.org/patchwork/project/lkml/list/?series=439330


Thanks,
Chenyu

> --
> Len Brown, Intel Open Source Technology Center