Messages in this thread | | | Date | Fri, 31 Oct 2014 22:22:19 +0100 | Subject | Re: [RFD] perf syscall error handling | From | Stephane Eranian <> |
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Hi,
On Fri, Oct 31, 2014 at 1:28 PM, Matt Fleming <matt@console-pimps.org> wrote: > On Fri, 31 Oct, at 10:27:13AM, Ingo Molnar wrote: >> >> - user-space gets back the regular errno (-EOPNOTSUPP or -ENOSYS >> or -EINVAL, etc.) and a string. Strings are really the most >> helpful information, because tools can just print that. They >> can also match on specific strings and programmatically react >> to them if they want to: we can promise to not arbitrarily >> change error strings once they are introduced. (but even if >> they change, user-space can still print them out.) > > I guess we'd run into a problem if userspace doesn't want to just print > the kernel string but instead wants to parse it in some fashion. > > That may or may not be a problem in practice, Vince can probably comment > on that. I'm just thinking along the lines of making the perf syscall > interface as useful as possible for tools other than tools/perf. > Maybe I missed something in the earlier thread, but I am trying to understand why perf_event_open() would need such extended error retrieval system when no other syscall does.
In any case, I would go with Ingo's proposal.
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