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From: Wei Liu <wei.liu2@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>,
	Joao Martins <joao.m.martins@oracle.com>,
	Wei Liu <wei.liu2@citrix.com>,
	Dario Faggioli <dario.faggioli@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH] x86/time: use correct (local) time stamp in constant-TSC calibration fast path
Date: Thu, 9 Jun 2016 13:12:33 +0100	[thread overview]
Message-ID: <20160609121233.GL28116@citrix.com> (raw)
In-Reply-To: <575976AE02000078000F3695@prv-mh.provo.novell.com>

On Thu, Jun 09, 2016 at 06:01:18AM -0600, Jan Beulich wrote:
> This looks like a copy and paste mistake in commit 1b6a99892d ("x86:
> Simpler time handling when TSC is constant across all power saving
> states"), responsible for occasional many-microsecond cross-CPU skew of
> what NOW() returns.
> 
> Also improve the correlation between local TSC and stime stamps
> obtained at the end of the two calibration handlers: Compute the stime
> one from the TSC one, instead of doing another rdtsc() for that
> compuation.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> ---
> As to 4.7 inclusion: This of course looks like a pretty blatant mistake
> that has been there for many years (and hence many releases). There's
> certainly non-zero risk that I'm overlooking something here (despite
> Joao apparently having come to the same conclusion), so I can't really
> make up my mind on whether to request this patch to be put there right
> away, or rather having linger in -unstable for a while.
> 

Leave it in unstable for a while please.

I don't want to delay the release any further.

Wei.


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      parent reply	other threads:[~2016-06-09 12:12 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-09 12:01 Jan Beulich
2016-06-09 12:10 ` Andrew Cooper
2016-06-09 12:11 ` Joao Martins
2016-06-09 12:57   ` Jan Beulich
2016-06-09 15:00     ` Joao Martins
2016-06-09 15:52       ` Jan Beulich
2016-06-09 18:19         ` Joao Martins
2016-06-10  6:59           ` Jan Beulich
2016-06-10  9:29             ` Jan Beulich
2016-06-10 17:07               ` Joao Martins
2016-06-09 12:12 ` Wei Liu [this message]

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