Re: [PATCH v5 11/16] perf report: properly handle branch count in match_chain

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Fri, Oct 13, 2017 at 10:39:03AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Mon, Oct 09, 2017 at 10:33:05PM +0200, Milian Wolff escreveu:
> > Some of the code paths I introduced before returned too early
> > without running the code to handle a node's branch count.
> > By refactoring match_chain to only have one exit point, this
> > can be remedied.
> 
> Fixing up this one now.

Millian, this is all fresher in your mind, can you please take a look at
my perf/core branch and check if the change i made to ]PATCH v5 09/16]
"perf report: compare symbol name for inlined frames when matching" is
ok wrt Ravi's fix and then, please, rebase v5 on top of what is there?

Ravi, please take a look at this as well, to see if with these changes
your fix remains valid, ok?

Thanks,

- Arnaldo
  
> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> > Cc: David Ahern <dsahern@gmail.com>
> > Cc: Namhyung Kim <namhyung@kernel.org>
> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > Cc: Yao Jin <yao.jin@linux.intel.com>
> > Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
> > ---
> >  tools/perf/util/callchain.c | 117 +++++++++++++++++++++++---------------------
> >  1 file changed, 60 insertions(+), 57 deletions(-)
> > 
> > diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
> > index 3f1431bf71bd..782de047c902 100644
> > --- a/tools/perf/util/callchain.c
> > +++ b/tools/perf/util/callchain.c
> > @@ -666,78 +666,81 @@ static enum match_result match_chain_strings(const char *left,
> >  	return ret;
> >  }
> >  
> > +static enum match_result match_address(u64 left, u64 right)
> > +{
> > +	if (left == right)
> > +		return MATCH_EQ;
> > +	else if (left < right)
> > +		return MATCH_LT;
> > +	else
> > +		return MATCH_GT;
> > +}
> > +
> >  static enum match_result match_chain(struct callchain_cursor_node *node,
> >  				     struct callchain_list *cnode)
> >  {
> > -	struct symbol *sym = node->sym;
> > -	enum match_result match;
> > -	u64 left, right;
> > +	enum match_result match = MATCH_ERROR;
> >  
> > -	if (callchain_param.key == CCKEY_SRCLINE) {
> > +	switch (callchain_param.key) {
> > +	case CCKEY_SRCLINE:
> >  		match = match_chain_strings(cnode->srcline, node->srcline);
> > -
> > -		/* if no srcline is available, fallback to symbol name */
> > -		if (match == MATCH_ERROR && cnode->ms.sym && node->sym)
> > -			match = match_chain_strings(cnode->ms.sym->name,
> > -						    node->sym->name);
> > -
> >  		if (match != MATCH_ERROR)
> > -			return match;
> > -
> > -		/* otherwise fall-back to IP-based comparison below */
> > -	}
> > -
> > -	if (cnode->ms.sym && sym && callchain_param.key == CCKEY_FUNCTION) {
> > -		/* compare inlined frames based on their symbol name because
> > -		 * different inlined frames will have the same symbol start
> > -		 */
> > -		if (cnode->ms.sym->inlined || node->sym->inlined)
> > -			return match_chain_strings(cnode->ms.sym->name,
> > -						   node->sym->name);
> > -
> > -		left = cnode->ms.sym->start;
> > -		right = sym->start;
> > -	} else {
> > -		left = cnode->ip;
> > -		right = node->ip;
> > +			break;
> > +		__fallthrough;
> > +	case CCKEY_FUNCTION:
> > +		if (node->sym && cnode->ms.sym) {
> > +			/* compare inlined frames based on their symbol name
> > +			 * because different inlined frames will have the same
> > +			 * symbol start. otherwise do a faster comparison based
> > +			 * on the symbol start address
> > +			 */
> > +			if (cnode->ms.sym->inlined || node->sym->inlined)
> > +				match = match_chain_strings(cnode->ms.sym->name,
> > +							    node->sym->name);
> > +			else
> > +				match = match_address(cnode->ms.sym->start,
> > +						      node->sym->start);
> > +			if (match != MATCH_ERROR)
> > +				break;
> > +		}
> > +		__fallthrough;
> > +	case CCKEY_ADDRESS:
> > +	default:
> > +		match = match_address(cnode->ip, node->ip);
> > +		break;
> >  	}
> >  
> > -	if (left == right) {
> > -		if (node->branch) {
> > -			cnode->branch_count++;
> > +	if (match == MATCH_EQ && node->branch) {
> > +		cnode->branch_count++;
> >  
> > -			if (node->branch_from) {
> > -				/*
> > -				 * It's "to" of a branch
> > -				 */
> > -				cnode->brtype_stat.branch_to = true;
> > +		if (node->branch_from) {
> > +			/*
> > +			 * It's "to" of a branch
> > +			 */
> > +			cnode->brtype_stat.branch_to = true;
> >  
> > -				if (node->branch_flags.predicted)
> > -					cnode->predicted_count++;
> > +			if (node->branch_flags.predicted)
> > +				cnode->predicted_count++;
> >  
> > -				if (node->branch_flags.abort)
> > -					cnode->abort_count++;
> > +			if (node->branch_flags.abort)
> > +				cnode->abort_count++;
> >  
> > -				branch_type_count(&cnode->brtype_stat,
> > -						  &node->branch_flags,
> > -						  node->branch_from,
> > -						  node->ip);
> > -			} else {
> > -				/*
> > -				 * It's "from" of a branch
> > -				 */
> > -				cnode->brtype_stat.branch_to = false;
> > -				cnode->cycles_count +=
> > -					node->branch_flags.cycles;
> > -				cnode->iter_count += node->nr_loop_iter;
> > -				cnode->iter_cycles += node->iter_cycles;
> > -			}
> > +			branch_type_count(&cnode->brtype_stat,
> > +					  &node->branch_flags,
> > +					  node->branch_from,
> > +					  node->ip);
> > +		} else {
> > +			/*
> > +			 * It's "from" of a branch
> > +			 */
> > +			cnode->brtype_stat.branch_to = false;
> > +			cnode->cycles_count += node->branch_flags.cycles;
> > +			cnode->iter_count += node->nr_loop_iter;
> > +			cnode->iter_cycles += node->iter_cycles;
> >  		}
> > -
> > -		return MATCH_EQ;
> >  	}
> >  
> > -	return left > right ? MATCH_GT : MATCH_LT;
> > +	return match;
> >  }
> >  
> >  /*
> > -- 
> > 2.14.2