| Message ID | CAO2gOZWm0yPV6zQjDGKrr6s2EwYEJYacK1EYHe62VOTy8FyCRQ@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
On Fri, Nov 8, 2013 at 6:23 AM, Dehao Chen <dehao@google.com> wrote: > AutoFDO sometimes has 0 profile in the loop's entry block because the > debug info are lost and unrecoverable. Is that a separate problem to track and fix? Also is it better to do a round of loop profiling smoothing after auto profile annotation to eliminate the insanity? David > > E.g. > > if (a) > if (b) > for () {} > > This patch checks if the scale factor is 0, then use the normal scale. > > Bootstrapped and passed regression test and performance test. > > OK for google-4_8? > > Thanks, > Dehao > > Index: gcc/cfgloopmanip.c > =================================================================== > --- gcc/cfgloopmanip.c (revision 204568) > +++ gcc/cfgloopmanip.c (working copy) > @@ -1262,6 +1262,8 @@ duplicate_loop_to_header_edge (struct loop *loop, > } > for (i = 0; i < ndupl; i++) > gcc_assert (scale_step[i] >= 0 && scale_step[i] <= REG_BR_PROB_BASE); > + if (flag_auto_profile && scale_main == 0) > + scale_main = REG_BR_PROB_BASE; > gcc_assert (scale_main >= 0 && scale_main <= REG_BR_PROB_BASE > && scale_act >= 0 && scale_act <= REG_BR_PROB_BASE); > }
As discussed offline, will commit this patch first, and think of other smoothing algorithm to prevent profile insanity. Dehao On Fri, Nov 8, 2013 at 9:32 AM, Xinliang David Li <davidxl@google.com> wrote: > On Fri, Nov 8, 2013 at 6:23 AM, Dehao Chen <dehao@google.com> wrote: >> AutoFDO sometimes has 0 profile in the loop's entry block because the >> debug info are lost and unrecoverable. > > Is that a separate problem to track and fix? > > > Also is it better to do a round of loop profiling smoothing after auto > profile annotation to eliminate the insanity? > > David > > >> >> E.g. >> >> if (a) >> if (b) >> for () {} >> >> This patch checks if the scale factor is 0, then use the normal scale. >> >> Bootstrapped and passed regression test and performance test. >> >> OK for google-4_8? >> >> Thanks, >> Dehao >> >> Index: gcc/cfgloopmanip.c >> =================================================================== >> --- gcc/cfgloopmanip.c (revision 204568) >> +++ gcc/cfgloopmanip.c (working copy) >> @@ -1262,6 +1262,8 @@ duplicate_loop_to_header_edge (struct loop *loop, >> } >> for (i = 0; i < ndupl; i++) >> gcc_assert (scale_step[i] >= 0 && scale_step[i] <= REG_BR_PROB_BASE); >> + if (flag_auto_profile && scale_main == 0) >> + scale_main = REG_BR_PROB_BASE; >> gcc_assert (scale_main >= 0 && scale_main <= REG_BR_PROB_BASE >> && scale_act >= 0 && scale_act <= REG_BR_PROB_BASE); >> }
Index: gcc/cfgloopmanip.c =================================================================== --- gcc/cfgloopmanip.c (revision 204568) +++ gcc/cfgloopmanip.c (working copy) @@ -1262,6 +1262,8 @@ duplicate_loop_to_header_edge (struct loop *loop, } for (i = 0; i < ndupl; i++) gcc_assert (scale_step[i] >= 0 && scale_step[i] <= REG_BR_PROB_BASE); + if (flag_auto_profile && scale_main == 0) + scale_main = REG_BR_PROB_BASE; gcc_assert (scale_main >= 0 && scale_main <= REG_BR_PROB_BASE && scale_act >= 0 && scale_act <= REG_BR_PROB_BASE); }
AutoFDO sometimes has 0 profile in the loop's entry block because the debug info are lost and unrecoverable. E.g. if (a) if (b) for () {} This patch checks if the scale factor is 0, then use the normal scale. Bootstrapped and passed regression test and performance test. OK for google-4_8? Thanks, Dehao