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Subject[PATCH 11/15 V3] perf, c2c: Add callchain support
Date
Seeing cacheline statistics is useful by itself.  Seeing the callchain
for these cache contentions saves time tracking things down.

This patch tries to add callchain support. I had to use the generic
interface from a previous patch to output things to stdout easily.

Other than the displaying the results, collecting the callchain and
merging it was fairly straightforward.

I used a lot of copying-n-pasting from other builtin tools to get
the intial parameter setup correctly and the automatic reading of
'symbol_conf.use_callchain' from the data file.

Hopefully this is all correct. The amount of memory corruption (from the
callchain dynamic array) seems to have dwindled done to nothing. :-)

V2: update to latest api
V3: remove call_graph variable, unused

Signed-off-by: Don Zickus <dzickus@redhat.com>
---
tools/perf/builtin-c2c.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 66 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index e3dbb76..363deec 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -79,6 +79,8 @@ struct c2c_hit {
u64 daddr;
u64 iaddr;
struct mem_info *mi;
+
+ struct callchain_root callchain[0]; /* must be last member */
};

enum { OP, LVL, SNP, LCK, TLB };
@@ -382,7 +384,8 @@ static int c2c_decode_stats(struct c2c_stats *stats, struct hist_entry *entry)

static struct c2c_hit *c2c_hit__new(u64 cacheline, struct hist_entry *entry)
{
- struct c2c_hit *h = zalloc(sizeof(struct c2c_hit));
+ size_t callchain_size = symbol_conf.use_callchain ? sizeof(struct callchain_root) : 0;
+ struct c2c_hit *h = zalloc(sizeof(struct c2c_hit) + callchain_size);

if (!h) {
pr_err("Could not allocate c2c_hit memory\n");
@@ -396,6 +399,8 @@ static struct c2c_hit *c2c_hit__new(u64 cacheline, struct hist_entry *entry)
h->cacheline = cacheline;
h->pid = entry->thread->pid_;
h->tid = entry->thread->tid;
+ if (symbol_conf.use_callchain)
+ callchain_init(h->callchain);

/* use original addresses here, not adjusted al_addr */
h->iaddr = entry->mem_info->iaddr.addr;
@@ -519,6 +524,10 @@ static int perf_c2c__process_load_store(struct perf_c2c *c2c,
return 0;
}

+ err = sample__resolve_callchain(sample, &parent, evsel, al, PERF_MAX_STACK_DEPTH);
+ if (err)
+ return err;
+
cost = sample->weight;
if (!cost)
cost = 1;
@@ -547,6 +556,7 @@ static int perf_c2c__process_load_store(struct perf_c2c *c2c,

c2c->hists.stats.total_period += cost;
hists__inc_nr_events(&c2c->hists, PERF_RECORD_SAMPLE);
+ err = hist_entry__append_callchain(he, sample);
return err;

out_mem:
@@ -948,6 +958,13 @@ static void print_hitm_cacheline_offset(struct c2c_hit *clo,
print_socket_shared_str(node_stats);

printf("\n");
+
+ if (symbol_conf.use_callchain) {
+ generic_entry_callchain__fprintf(clo->callchain,
+ h->stats.total_period,
+ clo->stats.total_period,
+ 23, stdout);
+ }
}

static void print_c2c_hitm_report(struct rb_root *hitm_tree,
@@ -1024,6 +1041,12 @@ static void print_c2c_hitm_report(struct rb_root *hitm_tree,
c2c_decode_stats(&node_stats[node], entry);
CPU_SET(entry->cpu, &(node_stats[node].cpuset));
}
+ if (symbol_conf.use_callchain) {
+ callchain_cursor_reset(&callchain_cursor);
+ callchain_merge(&callchain_cursor,
+ clo->callchain,
+ entry->callchain);
+ }

}
if (clo) {
@@ -1155,6 +1178,29 @@ err:
return err;
}

+static int perf_c2c__setup_sample_type(struct perf_c2c *c2c __maybe_unused,
+ struct perf_session *session)
+{
+ u64 sample_type = perf_evlist__combined_sample_type(session->evlist);
+
+ if (!(sample_type & PERF_SAMPLE_CALLCHAIN)) {
+ if (symbol_conf.use_callchain) {
+ printf("Selected -g but no callchain data. Did "
+ "you call 'perf c2c record' without -g?\n");
+ return -1;
+ }
+ } else if (callchain_param.mode != CHAIN_NONE &&
+ !symbol_conf.use_callchain) {
+ symbol_conf.use_callchain = true;
+ if (callchain_register_param(&callchain_param) < 0) {
+ printf("Can't register callchain params.\n");
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
static int perf_c2c__read_events(struct perf_c2c *c2c)
{
int err = -1;
@@ -1174,6 +1220,9 @@ static int perf_c2c__read_events(struct perf_c2c *c2c)
if (symbol__init() < 0)
goto out_delete;

+ if (perf_c2c__setup_sample_type(c2c, session) < 0)
+ goto out_delete;
+
/* setup the evsel handlers for each event type */
evlist__for_each(session->evlist, evsel) {
const char *name = perf_evsel__name(evsel);
@@ -1306,8 +1355,21 @@ opt_no_stores_cb(const struct option *opt __maybe_unused, const char *arg __mayb
return 0;
}

+static int
+opt_callchain_cb(const struct option *opt __maybe_unused, const char *arg, int unset)
+{
+ /*
+ * --no-call-graph
+ */
+ if (unset)
+ return 0;
+
+ return report_parse_callchain_opt(arg);
+}
+
int cmd_c2c(int argc, const char **argv, const char *prefix __maybe_unused)
{
+ char callchain_default_opt[] = "fractal,0.05,callee";
struct perf_c2c c2c = {
.tool = {
.sample = perf_c2c__process_sample,
@@ -1340,6 +1402,9 @@ int cmd_c2c(int argc, const char **argv, const char *prefix __maybe_unused)
"separator",
"separator for columns, no spaces will be added"
" between columns '.' is reserved."),
+ OPT_CALLBACK_DEFAULT('g', "call-graph", &c2c, "output_type,min_percent[,print_limit],call_order",
+ "Display callchains using output_type (graph, flat, fractal, or none) , min percent threshold, optional print limit, callchain order, key (function or address). "
+ "Default: fractal,0.5,callee,function", &opt_callchain_cb, callchain_default_opt),
OPT_END()
};
const char * const c2c_usage[] = {
--
1.7.11.7


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