Re: [PATCH 16/29] perf, tools: Add support for weight v7

[Stephane Eranian]

On Wed, Jan 23, 2013 at 6:13 PM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
>> For PEBS-LL and possibly other special cases, it is important to remember
>> that perf report always end up sorting by period (hist_collapse_resort). But
>> for PEBS-LL we want to sort on nr_events * weight. Thus, with your patch,
>> the only way, I found, to achieve this is by passing:
>>
>>        add_hist_entry(self, &entry, al, weight, weight);
>
> Seems like a hack. IMHO it should always sort by all the keys
> i specified with --sort in exactly that order I specified
>
Well, it does except for the "implicit" column which uses period, see
hists__collapse_resort().
And that function is hardcoded to only look at period.

As for the hack, I did not put in in my hist__add_mem_entry() but
rather in the caller.
For PEBS-LL, the period is not important. I think it counts the number
of loads/stores
and not just the qualifying ones. For loads, that means it counts all
loads and not just
the ones above the threshold, but I may be wrong.

> I had a similar thing in a really old version of my patches,
> but I gave it up because it was too unintuitive.
>
Well, but then it does not present a sensible view of the samples when weight is
more important than period.

> -Andi
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