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From: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Lameter <cl@linux.com>,
	Richard Cochran <richardcochran@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: Why do we still have 32 bit counters? Interrupt counters overflow within 50 days
Date: Mon, 6 Oct 2014 16:34:48 -0300	[thread overview]
Message-ID: <20141006193448.GB8238@khazad-dum.debian.net> (raw)
In-Reply-To: <alpine.DEB.2.11.1410061726510.4383@nanos>

> > Tools expect the number of interrupt to increase linearly and not jump by
> > 2^32 once in awhile. There are functions in the kernel (/proc/stat) that

...

> I understand that, I just wonder why nobody noticed before. It's been
> that way forever :)

Any proper tool that interfaces to snmp-like counters expects and deals with
worse: sudden counter resets.

And it has been that way forever :-)  So people who use such tools would
hardly notice any warp-arounds...

So, the question becomes: which tools are misbehaving?  Maybe they should
adopt snmp-like counter reset detection for peak filtering, and we could
leave 32-bit alone, and increase the counter size only on for 64-bit?

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh

  reply	other threads:[~2014-10-06 19:35 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-03  9:45 Why do we still have 32 bit counters? Interrupt counters overflow within 50 days Christoph Lameter
2014-10-03 10:33 ` Thomas Gleixner
2014-10-03 11:54   ` Christoph Lameter
2014-10-03 12:03     ` Richard Cochran
2014-10-03 12:07       ` Christoph Lameter
2014-10-03 12:17         ` Richard Cochran
2014-10-03 14:04           ` Christoph Lameter
2014-10-05 21:49         ` Thomas Gleixner
2014-10-05 23:24           ` Christoph Lameter
2014-10-05 23:57             ` Eric Dumazet
2014-10-06  8:06             ` Thomas Gleixner
2014-10-06 10:22               ` Christoph Lameter
2014-10-06 13:01                 ` Thomas Gleixner
2014-10-06 15:16                   ` Christoph Lameter
2014-10-06 15:28                     ` Thomas Gleixner
2014-10-06 19:34                       ` Henrique de Moraes Holschuh [this message]
2014-10-06 15:31                     ` David Lang
2014-10-06 19:45                       ` Christoph Lameter
2014-10-05 23:59           ` Eric Dumazet
2014-10-06  7:54             ` Thomas Gleixner
2014-10-06 10:49           ` David Lang
2014-10-06 12:28             ` Thomas Gleixner
2014-10-03 12:15     ` Paul Bolle
2014-10-03 12:23       ` Christoph Lameter
2014-10-04 10:26         ` Bernd Petrovitsch

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