| Message ID | CAO2gOZV1DYRb3p7ZNr=gkabWDm_dBxYHsfJ-VnwQm_SLxrgT9g@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
Looks good to me. Thanks, Teresa On Fri, Feb 28, 2014 at 2:17 PM, Dehao Chen <dehao@google.com> wrote: > This patch removes the size limit for loop unroll/peel when the loop > is truly hot. This makes the implementation easily maintanable between > FDO and AutoFDO. > > Bootstrapped and loadtest perf show neutral impact. > > OK for google-4_8? > > Thanks, > Dehao > > Index: gcc/loop-unroll.c > =================================================================== > --- gcc/loop-unroll.c (revision 208233) > +++ gcc/loop-unroll.c (working copy) > @@ -347,11 +347,9 @@ code_size_limit_factor(struct loop *loop) > /* Next, set the value of the codesize-based unroll factor divisor which in > most loops will need to be set to a value that will reduce or eliminate > unrolling/peeling. */ > - if (num_hot_counters < size_threshold * 2 > - && loop->header->count > 0) > + if (loop->header->count > 0) > { > - /* For applications that are less than twice the codesize limit, allow > - limited unrolling for very hot loops. */ > + /* Allow limited unrolling for very hot loops. */ > sum_to_header_ratio = profile_info->sum_all / loop->header->count; > hotness_ratio_threshold = PARAM_VALUE > (PARAM_UNROLLPEEL_HOTNESS_THRESHOLD); > /* When the profile count sum to loop entry header ratio is smaller than
Index: gcc/loop-unroll.c =================================================================== --- gcc/loop-unroll.c (revision 208233) +++ gcc/loop-unroll.c (working copy) @@ -347,11 +347,9 @@ code_size_limit_factor(struct loop *loop) /* Next, set the value of the codesize-based unroll factor divisor which in most loops will need to be set to a value that will reduce or eliminate unrolling/peeling. */ - if (num_hot_counters < size_threshold * 2 - && loop->header->count > 0) + if (loop->header->count > 0) { - /* For applications that are less than twice the codesize limit, allow - limited unrolling for very hot loops. */ + /* Allow limited unrolling for very hot loops. */ sum_to_header_ratio = profile_info->sum_all / loop->header->count; hotness_ratio_threshold = PARAM_VALUE (PARAM_UNROLLPEEL_HOTNESS_THRESHOLD);
This patch removes the size limit for loop unroll/peel when the loop is truly hot. This makes the implementation easily maintanable between FDO and AutoFDO. Bootstrapped and loadtest perf show neutral impact. OK for google-4_8? Thanks, Dehao /* When the profile count sum to loop entry header ratio is smaller than