From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vineet.Gupta1@synopsys.com (Vineet Gupta) Date: Thu, 12 May 2016 11:58:43 +0530 Subject: [RFC 2/2] perf/core: change errno for sampling event not supported in hardware In-Reply-To: <20160511193627.GH3190@twins.programming.kicks-ass.net> References: <1462786660-2900-1-git-send-email-vgupta@synopsys.com> <1462786660-2900-3-git-send-email-vgupta@synopsys.com> <5730C79F.3060307@synopsys.com> <20160511193627.GH3190@twins.programming.kicks-ass.net> List-ID: Message-ID: <5734229B.90706@synopsys.com> To: linux-snps-arc@lists.infradead.org On Thursday 12 May 2016 01:06 AM, Peter Zijlstra wrote: > On Mon, May 09, 2016@10:53:43PM +0530, Vineet Gupta wrote: > >> > Right thats what I feared. But hold on, I don't think we need to change the ABI to >> > achieve what we want. Gosh why did I even take that path. >> > >> > Currently the errno switch case in perf_evsel__open_strerror() in doesn't handle >> > ENOTSUPP. So how about we add that - augmented with the same sample_period !0 >> > check to barf for lack of sampling support. >> > >> > Do you see anything wrong with that ? > > Should work I think. Tried that and doesn't even compile. Reconfirms what Vince said, ENOTSUPP is not exposed to userspace (being in include/linux and not include/uapi/linux)