Re: perf eBPF patch ordering. was: Re: perf test LLVM was: Re: [GIT PULL 00/39] perf tools: filtering events using eBPF programs

["Wangnan (F)" <wangnan0@huawei.com>]

On 2015/8/1 4:31, Arnaldo Carvalho de Melo wrote:
> Em Fri, Jul 31, 2015 at 12:35:22PM -0300, Arnaldo Carvalho de Melo escreveu:
>> But point here is, when I see "enable passing
>> bpf object file to --event" I apply the patch and expect to be able to
>> go straight away and do:
>   
>>      perf record -e foo.o sleep 1
>   
>> And get some informative message as to hey, yes, I managed to do what
>> you asked or something is wrong, but I get:
>   
>>    [root@felicio ~]# perf record --event foo.o sleep
>>    event syntax error: 'foo.o'
>>                         \___ parser error
>>    Run 'perf list' for a list of valid events
>   
>>     usage: perf record [<options>] [<command>]
>>        or: perf record [<options>] -- <command> [<options>]
>   
>>        -e, --event <event>   event selector. use 'perf list' to list available events
>>    [root@felicio ~]#
>   
>> So, is it enabled or is it not? Doesn't look like. I.e. I think the best
>> thing is to only expose this when it can be used. Till that time, we can
> I just tried gdb'ing this with a breakpoint on parse_events_load_bpf(),
> but when I run:
>
>    (gdb) b parse_events_load_bpf
>    Breakpoint 1 at 0x48b11b: file util/parse-events.c, line 488.
>    (gdb) run record -e foo.o sleep 1
>    Starting program: /root/bin/perf record -e foo.o sleep 1
>    [Thread debugging using libthread_db enabled]
>    Using host libthread_db library "/lib64/libthread_db.so.1".
>    event syntax error: 'foo.o'
>                         \___ parser error
>    Run 'perf list' for a list of valid events
>
> Somehow it is not calling what the changeset says it would call when passing
> "-e foo.o", investigating...


Have you tried

/root/bin/perf record -e ./foo.o sleep 1

The key is './'.

I have reproduced the problem. Haven't noticed that because I always use './' name.

Will look into it.

Thank you, and glad to see you start looking at this cset.


> - Arnaldo