Messages in this thread Patch in this message | | | Subject | Re: [PATCH] perf parse-events: Set exclude_guest for user-space counting | From | Like Xu <> | Date | Thu, 13 Aug 2020 14:57:08 +0800 |
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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 > > 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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