Hi Brenden, thanks, I will double check my kernel settings.

On Sat, Oct 29, 2016 at 3:16 PM, Brenden Blanco <[email protected]> wrote:
>
>
> On Sat, Oct 29, 2016 at 1:27 AM, William Tu via iovisor-dev
> <[email protected]> wrote:
>>
>> Hi,
>>
>> I'm trying to measure the performance of my BPF programs, which attach
>> to clsact. As a start, I thought I could simply measure the cycles
>> spent on cls_bpf_classify(), because it's the wrapper calling into my
>> BPF programs.
>>
>> However, it seems that kprobe can not probe cls_bpf_classify(), even
>> though cls_bpf_classify isn't in NOKPROBE_SYMBOL. Is there any reason
>> why we couldn't probe it?
>>
>> [root@vm-dev bpf]# echo 'p:myprobe3 cls_bpf_classify' >>
>> /sys/kernel/debug/tracing/kprobe_events
>> bash: echo: write error: No such file or directory
>
>
> Worked for me:
>
> root@localhost:/sys/kernel/debug/tracing# echo 'p:myprobe3 cls_bpf_classify'
>> kprobe_events
> root@localhost:/sys/kernel/debug/tracing# cat events/kprobes/myprobe3/id
> 1256
>
>>
>>
>> As an alternative, I can probe on "__bpf_prog_run".
>> [root@vm-dev bpf]# echo 'p:myprobe4 __bpf_prog_run' >>
>> /sys/kernel/debug/tracing/kprobe_events
>>
>> Thanks
>> William
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>
>
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