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

From: Arnaldo Carvalho de Melo
Date: Fri Oct 13 2017 - 09:39:13 EST


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.

> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: David Ahern <dsahern@xxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> Cc: Yao Jin <yao.jin@xxxxxxxxxxxxxxx>
> Signed-off-by: Milian Wolff <milian.wolff@xxxxxxxx>
> ---
> 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