Re: [GOOGLE] Report the difference between profiled and guessed or annotated branch probabilities.

[Yi Yang <ahyangyi at google dot com>]

This is intermediate result, which is meant to be consumed by further
post-processing. For this reason I'd prefer to put a number without
that percentage sign.

I'd just output (int)(probability*100000000+0.5). Does this look good
for you? Or maybe change that to 1000000 since six digits are more
than enough. I don't see a reason to intentionally drop precision
though.

Note that for the actual probability, the best way to store it is to
store the edge count, since the probability is just
edge_count/bb_count. But this causes disparity in the formats of the
two probabilities.

On Mon, Jun 30, 2014 at 2:12 PM, Dehao Chen <dehao@google.com> wrote:
> Let's use %d to replace %f (manual conversion, let's do xx%).
>
> Dehao
>
> On Mon, Jun 30, 2014 at 2:06 PM, Yi Yang <ahyangyi@google.com> wrote:
>> Fixed.
>>
>> Also, I spotted some warnings caused by me using "%lf"s in snprintf().
>> I changed these to "%f" and tested.
>>
>>
>> On Mon, Jun 30, 2014 at 1:49 PM, Dehao Chen <dehao@google.com> wrote:
>>> You don't need extra space to store file name in locus_information_t.
>>> Use pointer instead.
>>>
>>> Dehao
>>>
>>>
>>> On Mon, Jun 30, 2014 at 1:36 PM, Yi Yang <ahyangyi@google.com> wrote:
>>>>
>>>> I refactored the code and added comments. A bug (prematurely breaking
>>>> from a loop) was fixed during the refactoring.
>>>>
>>>> (My last mail was wrongly set to HTML instead of plain text. I
>>>> apologize for that.)
>>>>
>>>> 2014-06-30  Yi Yang  <ahyangyi@google.com>
>>>>
>>>>     * auto-profile.c (get_locus_information)
>>>>     (fill_invalid_locus_information, record_branch_prediction_results)
>>>>     (afdo_calculate_branch_prob, afdo_annotate_cfg): Main comparison and
>>>>     reporting logic.
>>>>     * cfg-flags.def (PREDICTED_BY_EXPECT): Add an extra flag representing
>>>>     an edge's probability is predicted by annotations.
>>>>     * predict.c (combine_predictions_for_bb): Set up the extra flag on an
>>>>     edge when appropriate.
>>>>     * common.opt (fcheck-branch-annotation)
>>>>     (fcheck-branch-annotation-threshold=): Add an extra GCC option to turn
>>>>     on report
>>>>
>>>> On Fri, Jun 27, 2014 at 3:20 PM, Xinliang David Li <davidxl@google.com> wrote:
>>>> > Hi Yi,
>>>> >
>>>> > 1) please add comments before new functions as documentation -- follow
>>>> > the coding style guideline
>>>> > 2) missing documenation on the new flags (pointed out by Gerald)
>>>> > 3) Please refactor the check code in afdo_calculate_branch_prob into a
>>>> > helper function
>>>> >
>>>> > 4) the change log is not needed for google branches, but if provided,
>>>> > the format should follow the style guide (e.g, function name in () ).
>>>> >
>>>> > David
>>>> >
>>>> >
>>>> > On Fri, Jun 27, 2014 at 11:07 AM, Yi Yang <ahyangyi@google.com> wrote:
>>>> >> Hi,
>>>> >>
>>>> >> This patch adds an option. When the option is enabled, GCC will add a
>>>> >> record about it in an elf section called
>>>> >> ".gnu.switches.text.branch.annotation" for every branch.
>>>> >>
>>>> >> gcc/
>>>> >>
>>>> >> 2014-06-27 Yi Yang <ahyangyi@google.com>
>>>> >>
>>>> >>         * auto-profile.c: Main comparison and reporting logic.
>>>> >>         * cfg-flags.def: Add an extra flag representing an edge's
>>>> >> probability is predicted by annotations.
>>>> >>         * predict.c: Set up the extra flag on an edge when appropriate.
>>>> >>         * common.opt: Add an extra GCC option to turn on this report mechanism