Em Tue, Aug 25, 2020 at 03:54:37PM +0800, Jin, Yao escreveu: > Hi Arnaldo, > > On 8/19/2020 11:05 AM, Like Xu wrote: > > Hi Arnaldo, > > > > On 2020/8/17 10:32, Jin, Yao wrote: > > > 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? > > > > My concern is about do not break the perf kvm usages and Yao did it in v3. > > > > Tested-by: Like Xu <like...@linux.intel.com> > > > > Can this patch be accepted?
Sure. > > > > > > > > - 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? > > > > Do we really need to support sample guests without using perf kvm? > > > > If it's true, I would prefer "cycles:uG" to cover guest user space > > events only, "cycles:kG" to cover guest kernel space events only, > > and only host events are sampled without the ":G" modifier by default. > > > > I am not sure if ":G" has been used in perf. > > > > That may be another good idea I think. :) I have to check, but I don't think that :G is used. - Arnaldo