Messages in this thread | | | Subject | Re: [PATCH] perf parse-events: Set exclude_guest for user-space counting | From | "Jin, Yao" <> | Date | Thu, 13 Aug 2020 15:08:21 +0800 |
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On 8/13/2020 2:57 PM, Like Xu wrote: > Hi Yao, > > On 2020/8/13 11:11, Jin, Yao wrote: >> Hi Like, >> >> On 8/12/2020 9:02 PM, Like Xu wrote: >>> On 2020/8/12 20:15, Arnaldo Carvalho de Melo wrote: >>>> Em Wed, Aug 12, 2020 at 02:59:53PM +0800, Jin Yao escreveu: >>>>> Currently if we run 'perf record -e cycles:u', exclude_guest is 0. >>>>> >>>>> But it doesn't make sense that we request for user-space counting >>>>> but we also get the guest report. >>>>> >>> >>> Please hold the horse and allow this possibility. >>> >>> Some authorized perf users on the host may >>> only want to count (KVM) guest user space events. >>> >>> Thanks, >>> Like Xu >>> >> >> Without this patch, if we don't set the ":u" modifier, exclude_guest = 1. > > It's true for the non ":u" case. > >> >> perf record -e cycles ./div >> perf evlist -v >> cycles: size: 120, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|PERIOD, >> read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, >> sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1 >> >> So this patch doesn't change perf's original behavior. > > The patch changes the "perf kvm" original behavior. > > Testcase: perf kvm --host --guest --guestkallsyms=guest-kallsyms \ > --guestmodules=guest-modules record -e cycles:u ... > > From: > > cycles:u: size: 120, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|CPU|PERIOD, > read_format: ID, disabled: 1, inherit: 1, exclude_kernel: 1, exclude_hv: 1, freq: 1, sample_id_all: 1 > dummy:HG: type: 1, size: 120, config: 0x9, { sample_period, sample_freq }: 4000, sample_type: > IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, > sample_id_all: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1 > > To: > > cycles:u: size: 120, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|CPU|PERIOD, > read_format: ID, disabled: 1, inherit: 1, exclude_kernel: 1, exclude_hv: 1, freq: 1, sample_id_all: 1, > > exclude_guest: 1 > > dummy:HG: type: 1, size: 120, config: 0x9, { sample_period, sample_freq }: 4000, sample_type: > IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, > sample_id_all: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1 > > Thanks, > Like Xu
The behavior is similar as native kernel. The change of exclude_guest (0 -> 1) is expected.
On native kernel,
Before:
perf record -e cycles:u ./div perf evlist -v cycles:u: ..., exclude_kernel: 1, exclude_hv: 1, ...
After:
perf record -e cycles:u ./div perf evlist -v cycles:u: ..., exclude_kernel: 1, exclude_hv: 1, exclude_guest: 1, ...
Thanks Jin Yao
>> >> Thanks >> Jin Yao >> >>>>> To keep perf semantics consistent and clear, this patch sets >>>>> exclude_guest for user-space counting. >>>> >>>> Applied, and also added this, that you should consider doing in the >>>> future (modulo the "Committer testing:" header :) ): >>>> >>>> Committer testing: >>>> >>>> Before: >>>> >>>> # perf record -e cycles:u >>>> ^C[ perf record: Woken up 1 times to write data ] >>>> [ perf record: Captured and wrote 1.231 MB perf.data (91 samples) ] >>>> # >>>> # perf evlist -v >>>> cycles:u: size: 120, { sample_period, sample_freq }: 4000, sample_type: >>>> IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, disabled: 1, inherit: 1, exclude_kernel: 1, >>>> exclude_hv: 1, freq: 1, sample_id_all: 1 >>>> <SNIP> >>>> # >>>> >>>> After: >>>> >>>> # perf record -e cycles:u >>>> ^C[ perf record: Woken up 1 times to write data ] >>>> [ perf record: Captured and wrote 1.263 MB perf.data (403 samples) ] >>>> # >>>> # perf evlist -v >>>> cycles:u: size: 120, { sample_period, sample_freq }: 4000, sample_type: >>>> IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, disabled: 1, inherit: 1, exclude_kernel: 1, >>>> exclude_hv: 1, freq: 1, sample_id_all: 1, exclude_guest: 1 >>>> # >>>> >>>> ---- >>>> >>>> I.e. show actual command output before and after that demonstrates the >>>> problem and then the solution. >>>> >>>>> Signed-off-by: Jin Yao <yao.jin@linux.intel.com> >>>>> --- >>>>> tools/perf/util/parse-events.c | 2 ++ >>>>> 1 file changed, 2 insertions(+) >>>>> >>>>> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c >>>>> index 9f7260e69113..4d809f1fe269 100644 >>>>> --- a/tools/perf/util/parse-events.c >>>>> +++ b/tools/perf/util/parse-events.c >>>>> @@ -1794,6 +1794,8 @@ static int get_event_modifier(struct event_modifier *mod, char *str, >>>>> if (*str == 'u') { >>>>> if (!exclude) >>>>> exclude = eu = ek = eh = 1; >>>>> + if (!exclude_GH) >>>>> + eG = 1; >>>>> eu = 0; >>>>> } else if (*str == 'k') { >>>>> if (!exclude) >>>>> -- >>>>> 2.17.1 >>>>> >>>> >>> >
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