From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH] sched: add 64-bit counter retrieval API
Date: Mon, 23 Jul 2018 09:52:52 -0700
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Cc: cristian.dumitrescu@intel.com, dev@dpdk.org, Alan Dewar
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On Wed, 18 Jul 2018 15:51:39 +0100
alangordondewar@gmail.com wrote:

> From: Alan Dewar <alan.dewar@att.com>
> 
> Add new APIs to retrieve counters in 64-bit wide fields.
> 
> Signed-off-by: Alan Dewar <alan.dewar@att.com>

Do you want to consider 64 bit counter roll over on 32 bit platform?
The problem is that incrementing an 64 bit value is not atomic on
32 bit cpu. The carry operation can race with reading.

The kernel has special case code to do restartable sequence for
accessing 64 bit counter on 32 bit CPU. These functions become
nop's on 64bit.