| Message ID | 20121116003552.F236361423@tjsboxrox.mtv.corp.google.com |
|---|---|
| State | New |
| Headers | show |
> This patch addresses the bogus "Invocation mismatch" messages seen in parallel > profiledbootstrap builds of gcc. See PR bootstrap/55051 for a discussion of > why this is occurring and why this checking is inaccurate. > > Profilebootstrapped and tested on x86_64-unknown-linux-gnu. Ok for trunk? > > 2012-11-15 Teresa Johnson <tejohnson@google.com> > > PR bootstrap/55051 > * libgcov.c (gcov_exit): Remove checking against first > merged summary for program, as multiple simultaneous > processes attempting to update gcda files may cause > summaries to temporarily differ. > > Index: libgcov.c > =================================================================== > --- libgcov.c (revision 193522) > +++ libgcov.c (working copy) > @@ -365,7 +365,6 @@ gcov_exit (void) > struct gcov_info *gi_ptr; > const struct gcov_fn_info *gfi_ptr; > struct gcov_summary this_prg; /* summary for program. */ > - struct gcov_summary all_prg; /* summary for all instances of program. */ > struct gcov_ctr_summary *cs_ptr; > const struct gcov_ctr_info *ci_ptr; > unsigned t_ix; > @@ -382,7 +381,6 @@ gcov_exit (void) > if (gcov_dump_complete) > return; > > - memset (&all_prg, 0, sizeof (all_prg)); > /* Find the totals for this execution. */ > memset (&this_prg, 0, sizeof (this_prg)); > for (gi_ptr = gcov_list; gi_ptr; gi_ptr = gi_ptr->next) > @@ -469,7 +467,7 @@ gcov_exit (void) > unsigned n_counts; > struct gcov_summary prg; /* summary for this object over all > program. */ > - struct gcov_ctr_summary *cs_prg, *cs_tprg, *cs_all; > + struct gcov_ctr_summary *cs_prg, *cs_tprg; > int error = 0; > gcov_unsigned_t tag, length; > gcov_position_t summary_pos = 0; > @@ -684,7 +682,6 @@ gcov_exit (void) > { > cs_prg = &prg.ctrs[t_ix]; > cs_tprg = &this_prg.ctrs[t_ix]; > - cs_all = &all_prg.ctrs[t_ix]; > > if (gi_ptr->merge[t_ix]) > { > @@ -702,24 +699,6 @@ gcov_exit (void) > } > else if (cs_prg->runs) > goto read_mismatch; > - > - if (!cs_all->runs && cs_prg->runs) > - memcpy (cs_all, cs_prg, sizeof (*cs_all)); > - else if (!all_prg.checksum > - && (!GCOV_LOCKED || cs_all->runs == cs_prg->runs) > - /* Don't compare the histograms, which may have slight > - variations depending on the order they were updated > - due to the truncating integer divides used in the > - merge. */ > - && memcmp (cs_all, cs_prg, > - sizeof (*cs_all) - (sizeof (gcov_bucket_type) > - * GCOV_HISTOGRAM_SIZE))) Please keep the massage around with !GCOV_LOCKED. In that case user should be informed that parallel exeuction is bad idea (tm). The memcpy/memcmp pair with sizeof (gcov_bucket_type) adjustment is ugly. Just copy those few relevant values into temporary vars. OK with this change. Honza
Index: libgcov.c =================================================================== --- libgcov.c (revision 193522) +++ libgcov.c (working copy) @@ -365,7 +365,6 @@ gcov_exit (void) struct gcov_info *gi_ptr; const struct gcov_fn_info *gfi_ptr; struct gcov_summary this_prg; /* summary for program. */ - struct gcov_summary all_prg; /* summary for all instances of program. */ struct gcov_ctr_summary *cs_ptr; const struct gcov_ctr_info *ci_ptr; unsigned t_ix; @@ -382,7 +381,6 @@ gcov_exit (void) if (gcov_dump_complete) return; - memset (&all_prg, 0, sizeof (all_prg)); /* Find the totals for this execution. */ memset (&this_prg, 0, sizeof (this_prg)); for (gi_ptr = gcov_list; gi_ptr; gi_ptr = gi_ptr->next) @@ -469,7 +467,7 @@ gcov_exit (void) unsigned n_counts; struct gcov_summary prg; /* summary for this object over all program. */ - struct gcov_ctr_summary *cs_prg, *cs_tprg, *cs_all; + struct gcov_ctr_summary *cs_prg, *cs_tprg; int error = 0; gcov_unsigned_t tag, length; gcov_position_t summary_pos = 0; @@ -684,7 +682,6 @@ gcov_exit (void) { cs_prg = &prg.ctrs[t_ix]; cs_tprg = &this_prg.ctrs[t_ix]; - cs_all = &all_prg.ctrs[t_ix]; if (gi_ptr->merge[t_ix]) { @@ -702,24 +699,6 @@ gcov_exit (void) } else if (cs_prg->runs) goto read_mismatch; - - if (!cs_all->runs && cs_prg->runs) - memcpy (cs_all, cs_prg, sizeof (*cs_all)); - else if (!all_prg.checksum - && (!GCOV_LOCKED || cs_all->runs == cs_prg->runs) - /* Don't compare the histograms, which may have slight - variations depending on the order they were updated - due to the truncating integer divides used in the - merge. */ - && memcmp (cs_all, cs_prg, - sizeof (*cs_all) - (sizeof (gcov_bucket_type) - * GCOV_HISTOGRAM_SIZE))) - { - fprintf (stderr, "profiling:%s:Invocation mismatch - some data files may have been removed%s\n", - gi_filename, GCOV_LOCKED - ? "" : " or concurrently updated without locking support"); - all_prg.checksum = ~0u; - } } prg.checksum = crc32;
This patch addresses the bogus "Invocation mismatch" messages seen in parallel profiledbootstrap builds of gcc. See PR bootstrap/55051 for a discussion of why this is occurring and why this checking is inaccurate. Profilebootstrapped and tested on x86_64-unknown-linux-gnu. Ok for trunk? 2012-11-15 Teresa Johnson <tejohnson@google.com> PR bootstrap/55051 * libgcov.c (gcov_exit): Remove checking against first merged summary for program, as multiple simultaneous processes attempting to update gcda files may cause summaries to temporarily differ. -- This patch is available for review at http://codereview.appspot.com/6846063