Messages in this thread |  | | From | Vince Weaver <> | Date | Mon, 20 Apr 2015 10:42:56 -0400 (EDT) | Subject | Re: [patch 10/10] perf_event_open.2: 4.0 update rdpmc documentation |
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On Fri, 17 Apr 2015, Andy Lutomirski wrote: > On 04/16/2015 11:20 AM, Vince Weaver wrote: > > Probably a better change would have been to add "2" to mean per-process > > and make that the default setting. Probably too late to fix that now. > > Good point. I wish you'd thought of that sooner :(
Well it's been a busy semester and so I've had less time than normal to play perf_event ABI police.
I also was surprised this particular patch managed to get into 4.0 so quickly; I thought it was going to be a 4.1 change when I added it to my "changesets to look at more closely" list.
In any case most people won't notice this change. It will be a minor inconvenience for HPC people doing complicated homebrew self monitoring (especially if RHEL backports the patch and then suddenly things break and a simple "well are you running 4.0 or newer" is meaningless). Using the value in /sys/devices/cpu/rdpmc to help debug the problem wouldn't have worked anyway because it looks like non-root can't do that.
Vince
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