When I tried to analysis trace log that captured from xenomai system with kernelshark, I found
that it report "FAILED TO PARSE" for some events. These events have format like [1].
In trace, these events would be printed like [2].
At first, I was trying to develop new libtraceevent plugin to parse this event correctly.
When I refer to code plugins/plugin_mac80211.c of libtraceevent to parse field param_ex
out for this __data_loc type of data, I always get value 0x380018 and It is supposed to trace_seq_printf
0x38 size of string got from offset 0x18 of tep_record->data but it fail. After debug, I found
that the data start from offset 0x18 is not what we expect and first few bytes of data is like [3].
It seems that data stored for field param_ex is quite different from what we expect.
How could I look into trace-cmd related code to fix such issue? Any suggestions?
Thanks for your help in advance.
[1]:
root@ecs-xenomai-isar:~# cat /sys/kernel/debug/tracing/events/cobalt_posix/cobalt_pthread_create/format
name: cobalt_pthread_create
ID: 628
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:unsigned long pth; offset:8; size:8; signed:0;
field:int policy; offset:16; size:4; signed:1;
field:__data_loc char[] param_ex; offset:20; size:4; signed:1;
print fmt: "pth=%p policy=%s param=' %s '", (void *)REC->pth, __print_symbolic(REC->policy,
{0, "normal"}, {1, "fifo"}, {2, "rr"}, {11, "tp"}, {12, "quota"}, {10, "sporadic"}, {42, "cobalt"},
{43, "weak"}), cobalt_trace_parse_sched_params(p, REC->policy, (struct sched_param_ex *)(__get_dynamic_array(param_ex)))
[2]:
smokey-752 [000] d.~2 7970.727466: cobalt_pthread_getschedparam: pth=000000009bbc7fe0 policy=fifo param={ priority=50 }
smokey-762 [000] .... 7970.727492: cobalt_pthread_create: pth=00000000983468a5 policy=quota param={ priority=1, group=0 }
[3]:
0x1 0x0 0x0 0x0 0x0 0x0 0x0 0x0
Regards
Hongzhan Chen
|