Re: [PATCH 15/16] tracing: Add fields format definition for syscallevents

[Masami Hiramatsu]

Frederic Weisbecker wrote:
> Define the format of the syscall trace fields to parse the binary
> values from a raw trace using the syscall events "format" file.
> 
> This is defined dynamically using the syscalls metadata.
> It prepares the export of syscall event raw records to perf
> counters.
> 
> Example:
> 
> $ cat /debug/tracing/events/syscalls/sys_enter_sched_getparam/format
> name: sys_enter_sched_getparam
> ID: 39
> format:
> 	field:unsigned short common_type;	offset:0;	size:2;
> 	field:unsigned char common_flags;	offset:2;	size:1;
> 	field:unsigned char common_preempt_count;	offset:3;	size:1;
> 	field:int common_pid;	offset:4;	size:4;
> 	field:int common_tgid;	offset:8;	size:4;
> 
> 	field:pid_t pid;	offset:12;	size:8;
> 	field:struct sched_param * param;	offset:20;	size:8;
> 
> print fmt: "pid: 0x%08lx, param: 0x%08lx", ((unsigned long)(REC->pid)), ((unsigned long)(REC->param))

Hi Frederic,

I've found that the formats of some syscall events were too big.

---
$ for i in sys_enter* ;do grep name $i/format > /dev/null || echo $i has broken format. ; done sys_enter_getegid has broken format.
sys_enter_geteuid has broken format.
sys_enter_getgid has broken format.
sys_enter_getpgrp has broken format.
sys_enter_getpid has broken format.
sys_enter_getppid has broken format.
sys_enter_gettid has broken format.
sys_enter_getuid has broken format.
sys_enter_inotify_init has broken format.
sys_enter_munlockall has broken format.
sys_enter_pause has broken format.
sys_enter_restart_syscall has broken format.
sys_enter_sched_yield has broken format.
sys_enter_setsid has broken format.
sys_enter_sync has broken format.
sys_enter_vhangup has broken format.

$ cat sys_enter_getegid/format
FORMAT TOO BIG
---

And it causes an error on ./perf trace.

---
$ ./perf record -R -e syscalls:sys_enter_read -a -f  cat libperf.a > /dev/null

$ ./perf trace
  Fatal: Error: expected 'name' but read 'FORMAT'
version = 0.5
---

Thank you,

-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@xxxxxxxxxx

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