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Date: Mon, 17 Aug 2020 10:32:49 +0800 From: "Jin, Yao" <yao.jin@...ux.intel.com> To: Arnaldo Carvalho de Melo <acme@...nel.org> Cc: jolsa@...nel.org, peterz@...radead.org, mingo@...hat.com, alexander.shishkin@...ux.intel.com, Linux-kernel@...r.kernel.org, ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com, like.xu@...ux.intel.com Subject: Re: [PATCH v3] perf parse-events: Set exclude_guest=1 for user-space counting Hi Arnaldo, On 8/14/2020 8:47 PM, Arnaldo Carvalho de Melo wrote: > Em Fri, Aug 14, 2020 at 09:21:20AM +0800, Jin Yao escreveu: >> Currently if we run 'perf record -e cycles:u', exclude_guest=0. >> >> But it doesn't make sense in most cases that we request for >> user-space counting but we also get the guest report. >> >> Of course, we also need to consider perf kvm usage case that >> authorized perf users on the host may only want to count guest >> user space events. For example, >> >> perf kvm --guest record -e cycles:u > Ok, probably this works, but what if I want to record guest user samples > without using 'perf kvm'? > > Can we have a 'U' modifier, perhaps, for that? > > I.e. > > perf record -e cycles:uU would not set exclude_host not exclude_guest, > cycles:u excludes guest user, cycles:U excludes host user, would that be > possible? > > Anyway, I think that with what we have, your patch makes sense, having a > way to, without using 'perf kvm' still be able to sample the guest can > be done on top. of this. > > Xu, can we get your Reviewed-by if this addresses your concerns? > > - Arnaldo > Do you suggest we will create a new modifier 'U' as a follow-up patch? cycles:u - Count host user space but it doesn't count the guest user space (exclude_host = 0, exclude_guest = 1, exclude_kernel = 1, exclude_user = 0, exclude_hv = 1) cycles:U - Count the guest user space but it doesn't count the host user space (exclude_host = 1, exclude_guest = 0, exclude_kernel = 1, exclude_user = 0, exclude_hv = 1) Is above understanding correct? Thanks Jin Yao
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