Re: [google 4.7] fdo build for linux kernel (issue 6968046)

[Rong Xu <xur@google.com>]

that's right. but there is no way to predict the pattern.
what I meant was as far as it does not introduce major slow-down in
dumping profile, I'd like to use the simpler version.
what do you think?

-Rong

On Thu, Dec 20, 2012 at 11:54 AM, Xinliang David Li <davidxl@google.com> wrote:
> It  depends on the value distribution .
>
> David
>
> On Thu, Dec 20, 2012 at 11:30 AM, Rong Xu <xur@google.com> wrote:
>> On Wed, Dec 19, 2012 at 5:22 PM, Rong Xu <xur@google.com> wrote:
>>> On Wed, Dec 19, 2012 at 5:04 PM,  <davidxl@google.com> wrote:
>>>> The change in gcov-io.h is from a different patch.
>>>
>>> sorry. here is the patch for gcov-io.h:
>>>
>>> Index: gcov-io.h
>>> ===================================================================
>>> --- gcov-io.h   (revision 194562)
>>> +++ gcov-io.h   (working copy)
>>> @@ -781,8 +781,8 @@
>>>                                           unused) */
>>>
>>>    unsigned n_functions;                /* number of functions */
>>> -  const struct gcov_fn_info *const *functions; /* pointer to pointers
>>> -                                                 to function information  */
>>> +  const struct gcov_fn_info **functions; /* pointer to pointers
>>> +                                           to function information  */
>>>  };
>>>
>>>  /* Information about a single imported module.  */
>>> @@ -988,8 +988,7 @@
>>>  GCOV_LINKAGE void gcov_seek (gcov_position_t /*position*/) ATTRIBUTE_HIDDEN;
>>>  GCOV_LINKAGE void gcov_truncate (void) ATTRIBUTE_HIDDEN;
>>>  GCOV_LINKAGE gcov_unsigned_t gcov_string_length (const char *)
>>> ATTRIBUTE_HIDDEN;
>>> -GCOV_LINKAGE unsigned gcov_gcda_file_size (struct gcov_info *,
>>> -                                           struct gcov_summary *);
>>> +GCOV_LINKAGE unsigned gcov_gcda_file_size (struct gcov_info *);
>>>  #else
>>>  /* Available outside libgcov */
>>>  GCOV_LINKAGE void gcov_sync (gcov_position_t /*base*/,
>>>
>>>>
>>>> David
>>>>
>>>>
>>>> https://codereview.appspot.com/6968046/diff/1/gcc/gcov-io.c
>>>> File gcc/gcov-io.c (right):
>>>>
>>>> https://codereview.appspot.com/6968046/diff/1/gcc/gcov-io.c#newcode688
>>>> gcc/gcov-io.c:688:
>>>> Have you compared this with this impl:
>>>>
>>>> while (x)
>>>> {
>>>>    c++;
>>>>    x&=(x-1)
>>>> }
>>>> return c;
>>>>
>>>
>>> I did not try this pimplier version. I can do a test on the dump speed
>>> and report back.
>>
>> This simpler version is about 2% slow in dumping the profiles (average
>> of 10 dumps). But this is not a big deal.
>> I'll use this this version.
>>
>> -Rong
>>
>>>
>>>> https://codereview.appspot.com/6968046/