From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <Ian.Campbell@citrix.com>
Subject: Re: [PATCH v2 2/5] tools: add routine to get CMT L3
 event mask
Date: Wed, 7 Jan 2015 17:04:38 +0000
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To: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: wei.liu2@citrix.com, stefano.stabellini@eu.citrix.com, Andrew Cooper <andrew.cooper3@citrix.com>, xen-devel@lists.xen.org, JBeulich@suse.com, Chao Peng <chao.p.peng@linux.intel.com>, keir@xen.org
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On Wed, 2015-01-07 at 16:37 +0000, Ian Jackson wrote:
> >  As the result of the hypercall is going to be the same, the
> > worse that a race could achieve is a wasted hypercall.
> 
> This kind of analysis is unfounded in the presence of modern compilers
> with aggressive optimisations.  At the very least, if you're going to
> do some caching like this, it needs a lock around it.

Even for a hypercall which is just "return 42" (at least between boots)?

Ian.