perf trace + BPF
From: Arnaldo Carvalho de Melo
Date: Thu Mar 31 2016 - 14:08:17 EST
Hi Wang,
Trying to get back at working with 'perf trace' + BPF and I'm
noticing that the perf_event_attr->sample_type for the BPF events are
different than the ones for the raw_syscalls:sys_{enter,exit} or to
other tracepoint events we may ask 'perf trace' to set up, for instance,
for:
perf trace -vv -T --ev sched:sched_switch --ev bpf-output/no-inherit,name=evt/ --ev /home/acme/bpf/test_bpf_trace.c/map:channel.event=evt/ usleep 10
We get these sample types (full perf_event_attr dump at the end of this
message):
sched:sched_switch:
sample_type IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER
[root@jouet ~]# perf probe -l
perf_bpf_probe:func_begin (on SyS_nanosleep@linux/kernel/time/hrtimer.c)
perf_bpf_probe:func_end (on SyS_nanosleep%return@linux/kernel/time/hrtimer.c)
sample_type IP|TID|RAW|IDENTIFIER
raw_syscalls:sys_{enter,exit}:
sample_type IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER
I guess this is an interaction with that "no-inherit" part, probably we need to
set PERF_SAMPLE_TIME by some other means...
- Arnaldo
------------------------------------------------------------
perf_event_attr:
type 2
size 112
config 0x110
{ sample_period, sample_freq } 1
sample_type IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER
read_format ID
disabled 1
inherit 1
mmap 1
comm 1
enable_on_exec 1
task 1
sample_id_all 1
exclude_guest 1
mmap2 1
comm_exec 1
{ wakeup_events, wakeup_watermark } 1
------------------------------------------------------------
sys_perf_event_open: pid 32425 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 1 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 2 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 3 group_fd -1 flags 0x8
------------------------------------------------------------
perf_event_attr:
type 1
size 112
config 0xa
{ sample_period, sample_freq } 1
sample_type IP|TID|RAW|IDENTIFIER
read_format ID
disabled 1
enable_on_exec 1
sample_id_all 1
exclude_guest 1
{ wakeup_events, wakeup_watermark } 1
------------------------------------------------------------
sys_perf_event_open: pid 32425 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 1 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 2 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 3 group_fd -1 flags 0x8
------------------------------------------------------------
perf_event_attr:
type 2
size 112
config 0x7c5
{ sample_period, sample_freq } 1
sample_type IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER
read_format ID
disabled 1
inherit 1
enable_on_exec 1
sample_id_all 1
exclude_guest 1
{ wakeup_events, wakeup_watermark } 1
------------------------------------------------------------
sys_perf_event_open: pid 32425 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 1 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 2 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 3 group_fd -1 flags 0x8
------------------------------------------------------------
perf_event_attr:
type 2
size 112
config 0x7c4
{ sample_period, sample_freq } 1
sample_type IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER
read_format ID
disabled 1
inherit 1
enable_on_exec 1
sample_id_all 1
exclude_guest 1
{ wakeup_events, wakeup_watermark } 1
------------------------------------------------------------
sys_perf_event_open: pid 32425 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 1 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 2 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 3 group_fd -1 flags 0x8
------------------------------------------------------------
perf_event_attr:
type 2
size 112
config 0x11
{ sample_period, sample_freq } 1
sample_type IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER
read_format ID
disabled 1
inherit 1
enable_on_exec 1
sample_id_all 1
exclude_guest 1
{ wakeup_events, wakeup_watermark } 1
------------------------------------------------------------
sys_perf_event_open: pid 32425 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 1 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 2 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 3 group_fd -1 flags 0x8
------------------------------------------------------------
perf_event_attr:
type 2
size 112
config 0x10
{ sample_period, sample_freq } 1
sample_type IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER
read_format ID
disabled 1
inherit 1
enable_on_exec 1
sample_id_all 1
exclude_guest 1
{ wakeup_events, wakeup_watermark } 1
------------------------------------------------------------
sys_perf_event_open: pid 32425 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 1 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 2 group_fd -1 flags 0x8
sys_perf_event_open: pid 32425 cpu 3 group_fd -1 flags 0x8
mmap size 528384B