Messages in this thread | | | Date | Mon, 10 Sep 2012 15:07:00 +0200 | From | Robert Richter <> | Subject | Re: [PATCH] perf, ibs: Check syscall attribute flags |
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On 07.09.12 11:20:19, David Ahern wrote: > I see now... intel returns ENOTSUP if exclude_guest is not set, amd > returns EINVAL if it is set. > > For the AMD case the fallback_missing_features code kicks in for > perf-top and perf-record; I just need to fix up the pr_debug for that case.
It is EOPNOTSUP. I preferred returning EOPNOTSUP too. But then I saw that fallback code is implemented to work mostly with EINVAL. It seems to be the default answer to a syscall. ;)
There are several pieces of code in perf that implement fallback code, it's hard to find it all and this already caused some bugs in the past. I was looking at this to unify it, but it was too much effort.
-Robert
-- Advanced Micro Devices, Inc. Operating System Research Center
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