[PATCH] perf evsel: Adjust hybrid event and global event mixed group
From: Jin Yao
Date: Mon May 31 2021 - 21:40:49 EST
A group mixed with hybrid event and global event is allowed. For example,
group leader is 'intel_pt//' and the group member is 'cpu_atom/cycles/'.
e.g.
perf record --aux-sample -e '{intel_pt//,cpu_atom/cycles/}:u'
The challenge is their available cpus are not fully matched. For example,
'intel_pt//' is available on CPU0-CPU23, but 'cpu_atom/cycles/' is
available on CPU16-CPU23.
When getting the group id for group member, we must be very careful.
Because the cpu for 'intel_pt//' is not equal to the cpu for
'cpu_atom/cycles/'. Actually the cpu here is the index of evsel->core.cpus,
not the real CPU ID.
e.g. cpu0 for 'intel_pt//' is CPU0, but cpu0 for 'cpu_atom/cycles/' is CPU16.
Before:
# perf record --aux-sample -e '{intel_pt//,cpu_atom/cycles/}:u' -vv uname
...
------------------------------------------------------------
perf_event_attr:
type 10
size 128
config 0xe601
{ sample_period, sample_freq } 1
sample_type IP|TID|TIME|CPU|IDENTIFIER
read_format ID
disabled 1
inherit 1
exclude_kernel 1
exclude_hv 1
enable_on_exec 1
sample_id_all 1
exclude_guest 1
------------------------------------------------------------
sys_perf_event_open: pid 4084 cpu 0 group_fd -1 flags 0x8 = 5
sys_perf_event_open: pid 4084 cpu 1 group_fd -1 flags 0x8 = 6
sys_perf_event_open: pid 4084 cpu 2 group_fd -1 flags 0x8 = 7
sys_perf_event_open: pid 4084 cpu 3 group_fd -1 flags 0x8 = 9
sys_perf_event_open: pid 4084 cpu 4 group_fd -1 flags 0x8 = 10
sys_perf_event_open: pid 4084 cpu 5 group_fd -1 flags 0x8 = 11
sys_perf_event_open: pid 4084 cpu 6 group_fd -1 flags 0x8 = 12
sys_perf_event_open: pid 4084 cpu 7 group_fd -1 flags 0x8 = 13
sys_perf_event_open: pid 4084 cpu 8 group_fd -1 flags 0x8 = 14
sys_perf_event_open: pid 4084 cpu 9 group_fd -1 flags 0x8 = 15
sys_perf_event_open: pid 4084 cpu 10 group_fd -1 flags 0x8 = 16
sys_perf_event_open: pid 4084 cpu 11 group_fd -1 flags 0x8 = 17
sys_perf_event_open: pid 4084 cpu 12 group_fd -1 flags 0x8 = 18
sys_perf_event_open: pid 4084 cpu 13 group_fd -1 flags 0x8 = 19
sys_perf_event_open: pid 4084 cpu 14 group_fd -1 flags 0x8 = 20
sys_perf_event_open: pid 4084 cpu 15 group_fd -1 flags 0x8 = 21
sys_perf_event_open: pid 4084 cpu 16 group_fd -1 flags 0x8 = 22
sys_perf_event_open: pid 4084 cpu 17 group_fd -1 flags 0x8 = 23
sys_perf_event_open: pid 4084 cpu 18 group_fd -1 flags 0x8 = 24
sys_perf_event_open: pid 4084 cpu 19 group_fd -1 flags 0x8 = 25
sys_perf_event_open: pid 4084 cpu 20 group_fd -1 flags 0x8 = 26
sys_perf_event_open: pid 4084 cpu 21 group_fd -1 flags 0x8 = 27
sys_perf_event_open: pid 4084 cpu 22 group_fd -1 flags 0x8 = 28
sys_perf_event_open: pid 4084 cpu 23 group_fd -1 flags 0x8 = 29
------------------------------------------------------------
perf_event_attr:
size 128
config 0x800000000
{ sample_period, sample_freq } 4000
sample_type IP|TID|TIME|PERIOD|IDENTIFIER|AUX
read_format ID
inherit 1
exclude_kernel 1
exclude_hv 1
freq 1
sample_id_all 1
exclude_guest 1
aux_sample_size 4096
------------------------------------------------------------
sys_perf_event_open: pid 4084 cpu 16 group_fd 5 flags 0x8
sys_perf_event_open failed, error -22
The group_fd 5 is not correct. It should be 22 (the fd of
'intel_pt' on CPU16).
After:
# perf record --aux-sample -e '{intel_pt//,cpu_atom/cycles/}:u' -vv uname
...
------------------------------------------------------------
perf_event_attr:
type 10
size 128
config 0xe601
{ sample_period, sample_freq } 1
sample_type IP|TID|TIME|CPU|IDENTIFIER
read_format ID
disabled 1
inherit 1
exclude_kernel 1
exclude_hv 1
enable_on_exec 1
sample_id_all 1
exclude_guest 1
------------------------------------------------------------
sys_perf_event_open: pid 5162 cpu 0 group_fd -1 flags 0x8 = 5
sys_perf_event_open: pid 5162 cpu 1 group_fd -1 flags 0x8 = 6
sys_perf_event_open: pid 5162 cpu 2 group_fd -1 flags 0x8 = 7
sys_perf_event_open: pid 5162 cpu 3 group_fd -1 flags 0x8 = 9
sys_perf_event_open: pid 5162 cpu 4 group_fd -1 flags 0x8 = 10
sys_perf_event_open: pid 5162 cpu 5 group_fd -1 flags 0x8 = 11
sys_perf_event_open: pid 5162 cpu 6 group_fd -1 flags 0x8 = 12
sys_perf_event_open: pid 5162 cpu 7 group_fd -1 flags 0x8 = 13
sys_perf_event_open: pid 5162 cpu 8 group_fd -1 flags 0x8 = 14
sys_perf_event_open: pid 5162 cpu 9 group_fd -1 flags 0x8 = 15
sys_perf_event_open: pid 5162 cpu 10 group_fd -1 flags 0x8 = 16
sys_perf_event_open: pid 5162 cpu 11 group_fd -1 flags 0x8 = 17
sys_perf_event_open: pid 5162 cpu 12 group_fd -1 flags 0x8 = 18
sys_perf_event_open: pid 5162 cpu 13 group_fd -1 flags 0x8 = 19
sys_perf_event_open: pid 5162 cpu 14 group_fd -1 flags 0x8 = 20
sys_perf_event_open: pid 5162 cpu 15 group_fd -1 flags 0x8 = 21
sys_perf_event_open: pid 5162 cpu 16 group_fd -1 flags 0x8 = 22
sys_perf_event_open: pid 5162 cpu 17 group_fd -1 flags 0x8 = 23
sys_perf_event_open: pid 5162 cpu 18 group_fd -1 flags 0x8 = 24
sys_perf_event_open: pid 5162 cpu 19 group_fd -1 flags 0x8 = 25
sys_perf_event_open: pid 5162 cpu 20 group_fd -1 flags 0x8 = 26
sys_perf_event_open: pid 5162 cpu 21 group_fd -1 flags 0x8 = 27
sys_perf_event_open: pid 5162 cpu 22 group_fd -1 flags 0x8 = 28
sys_perf_event_open: pid 5162 cpu 23 group_fd -1 flags 0x8 = 29
------------------------------------------------------------
perf_event_attr:
size 128
config 0x800000000
{ sample_period, sample_freq } 4000
sample_type IP|TID|TIME|PERIOD|IDENTIFIER|AUX
read_format ID
inherit 1
exclude_kernel 1
exclude_hv 1
freq 1
sample_id_all 1
exclude_guest 1
aux_sample_size 4096
------------------------------------------------------------
sys_perf_event_open: pid 5162 cpu 16 group_fd 22 flags 0x8 = 30
sys_perf_event_open: pid 5162 cpu 17 group_fd 23 flags 0x8 = 31
sys_perf_event_open: pid 5162 cpu 18 group_fd 24 flags 0x8 = 32
sys_perf_event_open: pid 5162 cpu 19 group_fd 25 flags 0x8 = 33
sys_perf_event_open: pid 5162 cpu 20 group_fd 26 flags 0x8 = 34
sys_perf_event_open: pid 5162 cpu 21 group_fd 27 flags 0x8 = 35
sys_perf_event_open: pid 5162 cpu 22 group_fd 28 flags 0x8 = 36
sys_perf_event_open: pid 5162 cpu 23 group_fd 29 flags 0x8 = 37
------------------------------------------------------------
...
Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
tools/perf/util/evsel.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 4a3cd1b5bb33..a9cf615fe580 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1581,6 +1581,15 @@ int __evsel__read_on_cpu(struct evsel *evsel, int cpu, int thread, bool scale)
return 0;
}
+static int evsel_cpuid_match(struct evsel *evsel1, struct evsel *evsel2,
+ int cpu)
+{
+ int cpuid;
+
+ cpuid = perf_cpu_map__cpu(evsel1->core.cpus, cpu);
+ return perf_cpu_map__idx(evsel2->core.cpus, cpuid);
+}
+
static int get_group_fd(struct evsel *evsel, int cpu, int thread)
{
struct evsel *leader = evsel->leader;
@@ -1595,6 +1604,26 @@ static int get_group_fd(struct evsel *evsel, int cpu, int thread)
*/
BUG_ON(!leader->core.fd);
+ /*
+ * If leader is global event (e.g. 'intel_pt//'), but member is
+ * hybrid event. Need to get the leader's fd from correct cpu.
+ */
+ if (evsel__is_hybrid(evsel) &&
+ !evsel__is_hybrid(leader)) {
+ cpu = evsel_cpuid_match(evsel, leader, cpu);
+ BUG_ON(cpu == -1);
+ }
+
+ /*
+ * Leader is hybrid event but member is global event.
+ */
+ if (!evsel__is_hybrid(evsel) &&
+ evsel__is_hybrid(leader)) {
+ cpu = evsel_cpuid_match(evsel, leader, cpu);
+ if (cpu == -1)
+ return -1;
+ }
+
fd = FD(leader, cpu, thread);
BUG_ON(fd == -1);
--
2.17.1