Per the hackery I did:
https://lkml.kernel.org/r/[email protected]
The userspace bits need something like so on top..
---
tools/perf/util/callchain.c | 2 +-
tools/perf/util/evsel.c | 10 +++++++---
tools/perf/util/perf_event_attr_fprintf.c | 1 +
3 files changed, 9 insertions(+), 4 deletions(-)
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -1832,7 +1832,7 @@ int sample__for_each_callchain_node(stru
int sample__merge_deferred_callchain(struct perf_sample *sample_orig,
struct perf_sample *sample_callchain)
{
- u64 nr_orig = sample_orig->callchain->nr - PERF_DEFERRED_ITEMS;
+ u64 nr_orig = sample_orig->callchain->nr - 1;
u64 nr_deferred = sample_callchain->callchain->nr;
struct ip_callchain *callchain;
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1520,6 +1520,7 @@ void evsel__config(struct evsel *evsel,
attr->mmap2 = track && !perf_missing_features.mmap2;
attr->comm = track;
attr->build_id = track && opts->build_id;
+ attr->defer_output = track && !perf_missing_features.defer_callchain;
/*
* ksymbol is tracked separately with text poke because it needs to be
@@ -2206,8 +2207,10 @@ static int __evsel__prepare_open(struct
static void evsel__disable_missing_features(struct evsel *evsel)
{
- if (perf_missing_features.defer_callchain)
+ if (perf_missing_features.defer_callchain) {
evsel->core.attr.defer_callchain = 0;
+ evsel->core.attr.defer_output = 0;
+ }
if (perf_missing_features.inherit_sample_read &&
evsel->core.attr.inherit &&
(evsel->core.attr.sample_type & PERF_SAMPLE_READ))
evsel->core.attr.inherit = 0;
@@ -2489,6 +2492,7 @@ static bool evsel__detect_missing_featur
perf_missing_features.defer_callchain = true;
pr_debug2("switching off deferred callchain support\n");
attr.defer_callchain = false;
+ attr.defer_output = false;
attr.sample_type = 0;
attr.inherit = true;
@@ -3255,8 +3259,8 @@ int evsel__parse_sample(struct evsel *ev
return -EFAULT;
sz = data->callchain->nr * sizeof(u64);
if (evsel->core.attr.defer_callchain &&
- data->callchain->nr >= PERF_DEFERRED_ITEMS &&
- data->callchain->ips[data->callchain->nr -
PERF_DEFERRED_ITEMS] == PERF_CONTEXT_USER_DEFERRED) {
+ data->callchain->nr >= 2 &&
+ data->callchain->ips[data->callchain->nr - 2] ==
PERF_CONTEXT_USER_DEFERRED) {
data->deferred_callchain = true;
data->deferred_cookie =
data->callchain->ips[data->callchain->nr - 1];
}
--- a/tools/perf/util/perf_event_attr_fprintf.c
+++ b/tools/perf/util/perf_event_attr_fprintf.c
@@ -344,6 +344,7 @@ int perf_event_attr__fprintf(FILE *fp, s
PRINT_ATTRf(remove_on_exec, p_unsigned);
PRINT_ATTRf(sigtrap, p_unsigned);
PRINT_ATTRf(defer_callchain, p_unsigned);
+ PRINT_ATTRf(defer_output, p_unsigned);
PRINT_ATTRn("{ wakeup_events, wakeup_watermark }", wakeup_events,
p_unsigned, false);
PRINT_ATTRf(bp_type, p_unsigned);
