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SubjectRe: [PATCH 00/10] perf tools: Use SIGUSR2 control data dumpping
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On 2016/4/16 0:48, Wangnan (F) wrote:
>
>
> On 2016/4/16 0:26, Arnaldo Carvalho de Melo wrote:
>> Em Fri, Apr 15, 2016 at 10:09:32AM -0300, Arnaldo Carvalho de Melo
>> escreveu:
>>> Em Fri, Apr 15, 2016 at 07:40:44PM +0800, Wangnan (F) escreveu:
>>>> On 2016/4/15 18:45, Wangnan (F) wrote:
>>>>> On 2016/4/15 18:40, Jiri Olsa wrote:
>>>>>> On Wed, Apr 13, 2016 at 08:21:03AM +0000, Wang Nan wrote:
>>>> [SNIP]
>>>>
>>>>>> I did not get 3/10 patch and the patchset did not apply cleanly,
>>>>>> git am failed.. would you have it in a branch somewhere?
>>>>> Sorry, you are not in the CC list. 'git send-email' failed to
>>>>> extract your
>>>>> email address from the Acked-by tag.
>>>>>
>>>>> I'll inform you after I putting them into a git branch. Please wait.
>>>>>
>>>>> Thank you.
>>>> I just realized Arnaldo has already collected these patches set into
>>>> his perf/core. Please see it in his git tree [1]. You can also have
>>>> a look
>>>> at my git tree [2] if you want :)
>>> I haven't pushed them to Ingo yet, so I can fix up things if Jiri has
>>> any fixes or other requests,
>> I moved those patches to a separate branch, perf/switch_output, till
>> we get a
>> bit more review, I think I was too fast on tentatively processing
>> this patchset
>> and have some questions, for instance, this part I thin really
>> confusing, in
>> the main record loop:
>>
>> switch_output_enable();
>> for (;;) {
>> unsigned long long hits = rec->samples;
>>
>> if (record__mmap_read_all(rec) < 0) {
>> auxtrace_snapshot_disable();
>> err = -1;
>> goto out_child;
>> }
>> <SNIP>
>> if (switch_output_is_disabled()) {
>> switch_output_enable();
>>
>> if (!quiet)
>> fprintf(stderr, "[ perf record: dump
>> data: Woken up %ld times ]\n",
>> waking);
>> waking = 0;
>> fd = record__switch_output(rec, false);
>> if (fd < 0) {
>> pr_err("Failed to switch to new
>> file\n");
>> err = fd;
>> goto out_child;
>> }
>> }
>> <SNIP>
>> }
>>
>> That switch_output_enable() one we can't get to because it is part of
>> that
>> trigger_ thing, so just by looking here we think switch_output is
>> being enabled
>> unconditionally, when in fact it will check if it is "OFF" and if so,
>> will not
>> "enable", then when we see switch_output_is_disabled() the question
>> will return
>> false if it is "OFF", but what we read is "hey, this is not disabled,
>> so it
>> must be enabled, no? Confusing :-\
>
> You are right. I think we should change the naming in trigger stuff:
>
> TRIGGER_OFF: this trigger is turned off
> TRIGGER_RELEASED: preparing to be triggered
> TRIGGER_TOGGLED: things happened
>
> actions:
>
> OFF -> RELEASED : on
> RELEASED -> TOGGLED: toggle
> TOGGLED-> RELEASED : release
>
> conditions:
>
> is_released()
> is_toggled()
>
> I'll send a v3 soon.
>
> Thank you.
>
>> Perhaps we should have multiple record loops, one really simple, the
>> original
>> one, one for auxtrace, that, from what we've discussed so far,
>> doesn't lok will
>> be supported together with output switch, and one for output switch?
>>
>> Would be something like:
>>
>> if (switch_output)
>> err = record__switch_output_read_events()
>> else if (auxtrace)
>> err = record__auxtrace_read_events()
>> else
>> err = record__read_events();
>>
>> And then each of these loops don't need to have all those branches
>> per mmap_read.
>>

Auxtrace and original events are not exclusive. Auxtrace and
switch_output are
not necessarily exclusive. At lease intel_bts// works fine. It is
intel_pt's own
limitation, not all auxtrace events.

Thank you.

>> - Arnaldo
>>> - Arnaldo
>>>> [1]
>>>> https://git.kernel.org/cgit/linux/kernel/git/acme/linux.git/commit/?h=perf/core&id=c0bdc1c461dd5b2e492c0746708a3e0da6b13515
>>>> [2]
>>>> https://git.kernel.org/cgit/linux/kernel/git/pi3orama/linux.git/log/?h=perf/overwrite
>


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