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Date: Thu, 23 Dec 2021 16:10:50 +0800
From: Yanling Song <songyl@ramaxel.com>
To: Stephen Hemminger <stephen@networkplumber.org>
CC: <dev@dpdk.org>, <yanling.song@linux.dev>, <yanggan@ramaxel.com>,
 <ferruh.yigit@intel.com>, <xuyun@ramaxel.com>
Subject: Re: [PATCH v1 01/25] drivers/net: introduce a new PMD driver
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On Wed, 22 Dec 2021 08:55:22 -0800
Stephen Hemminger <stephen@networkplumber.org> wrote:

> On Wed, 22 Dec 2021 08:54:00 +0800
> Yanling Song <songyl@ramaxel.com> wrote:
> 
> > > If all you want is jiffie accuracy,  you could use
> > > CLOCK_MONOTONIC_COARSE.
> > >     
> > I did not get your point: CLOCK_MONOTONIC is more accurate than
> > CLOCK_MONOTONIC_COARSE, right?  
> 
> CLOCK_MONOTONIC ends up using the TSC counter and values in the
> shared page (VDSO) to compute time accurately.
> 
> CLOCK_MONOTONIC_COARSE is faster and good enough if you only
> want ms accuracy. It just reads a value from shared page
> and avoids the TSC instruction.

OK. Got it. Thanks. Will be included in the next version.