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Date: Wed, 25 Oct 2017 11:09:14 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Milian Wolff <milian.wolff@...b.com>, jolsa@...nel.org,
linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
Andi Kleen <andi@...stfloor.org>,
Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>,
kernel-team@....com
Subject: Re: [PATCH v7 0/5] generate full callchain cursor entries for
inlined frames
Hi Arnaldo,
On Tue, Oct 24, 2017 at 10:27:42AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Mon, Oct 23, 2017 at 09:39:57PM +0200, Milian Wolff escreveu:
> > So to fix this all, I guess the suggested approach by Namhyung would be best,
> > i.e. fixup my initial match_addresses to take the map, and then if the map is
> > valid also take the dso into account when comparing the addresses:
> >
> > if (left_dso != right_dso)
> > return left_dso < right_dso ? MATCH_LT : MATCH_GT;
> > else if (left_ip != right_ip)
> > return left_ip < right_ip ? MATCH_LT : MATCH_GT;
> > else
> > return MATCH_EQ;
>
> So, can you check that the patch below is the one we should commit to?
> Namhyung? I'm looking at your latest patch kit, v7, to see if the branch
> parts, further below, are as you submitted or if I have any issues with
> it.
>
> I've updated my perf/core branch with all this.
>
> commit 275049196c64cc1233837c9f066b4b87e32cd1df
> Author: Milian Wolff <milian.wolff@...b.com>
> Date: Fri Oct 20 12:14:47 2017 -0300
>
> perf report: Properly handle branch count in match_chain()
>
> 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.
>
> Signed-off-by: Milian Wolff <milian.wolff@...b.com>
> Cc: David Ahern <dsahern@...il.com>
> Cc: Jin Yao <yao.jin@...ux.intel.com>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
> Cc: Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>
> Link: http://lkml.kernel.org/r/1707691.qaJ269GSZW@agathebauer
> Link: http://lkml.kernel.org/r/20171018185350.14893-2-milian.wolff@kdab.com
> Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Acked-by: Namhyung Kim <namhyung@...nel.org>
Thanks,
Namhyung
>
> diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
> index 35a920f09503..19bfcadcf891 100644
> --- a/tools/perf/util/callchain.c
> +++ b/tools/perf/util/callchain.c
> @@ -666,83 +666,99 @@ static enum match_result match_chain_strings(const char *left,
> return ret;
> }
>
> -static enum match_result match_chain(struct callchain_cursor_node *node,
> - struct callchain_list *cnode)
> +/*
> + * We need to always use relative addresses because we're aggregating
> + * callchains from multiple threads, i.e. different address spaces, so
> + * comparing absolute addresses make no sense as a symbol in a DSO may end up
> + * in a different address when used in a different binary or even the same
> + * binary but with some sort of address randomization technique, thus we need
> + * to compare just relative addresses. -acme
> + */
> +static enum match_result match_chain_dso_addresses(struct map *left_map, u64 left_ip,
> + struct map *right_map, u64 right_ip)
> {
> - struct symbol *sym = node->sym;
> - u64 left, right;
> - struct dso *left_dso = NULL;
> - struct dso *right_dso = NULL;
> + struct dso *left_dso = left_map ? left_map->dso : NULL;
> + struct dso *right_dso = right_map ? right_map->dso : NULL;
>
> - if (callchain_param.key == CCKEY_SRCLINE) {
> - enum match_result match = match_chain_strings(cnode->srcline,
> - node->srcline);
> + if (left_dso != right_dso)
> + return left_dso < right_dso ? MATCH_LT : MATCH_GT;
>
> - /* 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 (left_ip != right_ip)
> + return left_ip < right_ip ? MATCH_LT : MATCH_GT;
>
> - if (match != MATCH_ERROR)
> - return match;
> + return MATCH_EQ;
> +}
>
> - /* otherwise fall-back to IP-based comparison below */
> - }
> +static enum match_result match_chain(struct callchain_cursor_node *node,
> + struct callchain_list *cnode)
> +{
> + enum match_result match = MATCH_ERROR;
>
> - 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;
> - left_dso = cnode->ms.map->dso;
> - right_dso = node->map->dso;
> - } else {
> - left = cnode->ip;
> - right = node->ip;
> + switch (callchain_param.key) {
> + case CCKEY_SRCLINE:
> + match = match_chain_strings(cnode->srcline, node->srcline);
> + if (match != MATCH_ERROR)
> + break;
> + /* otherwise fall-back to symbol-based comparison below */
> + __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);
> + if (match != MATCH_ERROR)
> + break;
> + } else {
> + match = match_chain_dso_addresses(cnode->ms.map, cnode->ms.sym->start,
> + node->map, node->sym->start);
> + break;
> + }
> + }
> + /* otherwise fall-back to IP-based comparison below */
> + __fallthrough;
> + case CCKEY_ADDRESS:
> + default:
> + match = match_chain_dso_addresses(cnode->ms.map, cnode->ip, node->map, node->ip);
> + break;
> }
>
> - if (left == right && left_dso == right_dso) {
> - 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;
> }
>
> /*
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