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SubjectRe: [PATCH 2/2] perf top: support hotkey to change sort order
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On 3/20/2020 9:51 PM, Arnaldo Carvalho de Melo wrote:
> Em Fri, Mar 20, 2020 at 03:24:14PM +0800, Jin Yao escreveu:
>> It would be nice if we can use a hotkey in perf top browser to
>> select a event for sorting.
>>
>> For example,
>> perf top --group -e cycles,instructions,cache-misses
>>
>> Samples
>> Overhead Shared Object Symbol
>> 40.03% 45.71% 0.03% div [.] main
>> 20.46% 14.67% 0.21% libc-2.27.so [.] __random_r
>> 20.01% 19.54% 0.02% libc-2.27.so [.] __random
>> 9.68% 10.68% 0.00% div [.] compute_flag
>> 4.32% 4.70% 0.00% libc-2.27.so [.] rand
>> 3.84% 3.43% 0.00% div [.] rand@plt
>> 0.05% 0.05% 2.33% libc-2.27.so [.] __strcmp_sse2_unaligned
>> 0.04% 0.08% 2.43% perf [.] perf_hpp__is_dynamic_en
>> 0.04% 0.02% 6.64% perf [.] rb_next
>> 0.04% 0.01% 3.87% perf [.] dso__find_symbol
>> 0.04% 0.04% 1.77% perf [.] sort__dso_cmp
>>
>> When user press hotkey '2' (event index, starting from 0), it indicates
>> to sort output by the third event in group (cache-misses).
>>
>> Samples
>> Overhead Shared Object Symbol
>> 4.07% 1.28% 6.68% perf [.] rb_next
>> 3.57% 3.98% 4.11% perf [.] __hists__insert_output
>> 3.67% 11.24% 3.60% perf [.] perf_hpp__is_dynamic_e
>> 3.67% 3.20% 3.20% perf [.] hpp__sort_overhead
>> 0.81% 0.06% 3.01% perf [.] dso__find_symbol
>> 1.62% 5.47% 2.51% perf [.] hists__match
>> 2.70% 1.86% 2.47% libc-2.27.so [.] _int_malloc
>> 0.19% 0.00% 2.29% [kernel] [k] copy_page
>> 0.41% 0.32% 1.98% perf [.] hists__decay_entries
>> 1.84% 3.67% 1.68% perf [.] sort__dso_cmp
>> 0.16% 0.00% 1.63% [kernel] [k] clear_page_erms
>>
>> Now the output is sorted by cache-misses.
>>
>> Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
>> ---
>> tools/perf/builtin-top.c | 10 ++++++++--
>> 1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
>> index 144043637cec..b39f6ffb874e 100644
>> --- a/tools/perf/builtin-top.c
>> +++ b/tools/perf/builtin-top.c
>> @@ -616,6 +616,7 @@ static void *display_thread_tui(void *arg)
>> .arg = top,
>> .refresh = top->delay_secs,
>> };
>> + int ret;
>>
>> /* In order to read symbols from other namespaces perf to needs to call
>> * setns(2). This isn't permitted if the struct_fs has multiple users.
>> @@ -626,6 +627,7 @@ static void *display_thread_tui(void *arg)
>>
>> prctl(PR_SET_NAME, "perf-top-UI", 0, 0, 0);
>>
>> +repeat:
>> perf_top__sort_new_samples(top);
>>
>> /*
>> @@ -638,13 +640,17 @@ static void *display_thread_tui(void *arg)
>> hists->uid_filter_str = top->record_opts.target.uid_str;
>> }
>>
>> - perf_evlist__tui_browse_hists(top->evlist, help, &hbt,
>> + ret = perf_evlist__tui_browse_hists(top->evlist, help, &hbt,
>> top->min_percent,
>> &top->session->header.env,
>> !top->record_opts.overwrite,
>> &top->annotation_opts);
>>
>> - stop_top();
>> + if (ret == K_RELOAD)
>> + goto repeat;
>> + else
>> + stop_top();
>> +
>
> That is really nice and small, but shouldn't we flush all the histograms
> that were in place, sorted by the previous key? I think we have a 'z'
> for zeroing samples that may be what we need, take a look, please,
>
> - Arnaldo
>

Set top->zero to true if return key is K_RELOAD. So that in
perf_top__resort_hists(), it will delete hists entries by calling
hists__delete_entries(hists).

+repeat:
perf_top__sort_new_samples(top);

/*
@@ -638,13 +640,18 @@ static void *display_thread_tui(void *arg)
hists->uid_filter_str = top->record_opts.target.uid_str;
}

- perf_evlist__tui_browse_hists(top->evlist, help, &hbt,
+ ret = perf_evlist__tui_browse_hists(top->evlist, help, &hbt,
top->min_percent,
&top->session->header.env,
!top->record_opts.overwrite,
&top->annotation_opts);

- stop_top();
+ if (ret == K_RELOAD) {
+ top->zero = true;
+ goto repeat;
+ } else
+ stop_top();
+

Is this OK?

Thanks
Jin Yao

>> return NULL;
>> }
>> --
>> 2.17.1
>>
>

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