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Re: [PATCH V2 3/9] New commands `enable probe' and `disable probe'.
- From: Pedro Alves <palves at redhat dot com>
- To: "Jose E. Marchesi" <jose dot marchesi at oracle dot com>, Doug Evans <dje at google dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Fri, 17 Oct 2014 01:43:15 +0100
- Subject: Re: [PATCH V2 3/9] New commands `enable probe' and `disable probe'.
- Authentication-results: sourceware.org; auth=none
- References: <1412961772-16249-1-git-send-email-jose dot marchesi at oracle dot com> <1412961772-16249-4-git-send-email-jose dot marchesi at oracle dot com> <21560 dot 22449 dot 803178 dot 90104 at ruffy2 dot mtv dot corp dot google dot com> <878uknun2f dot fsf at oracle dot com> <5440649C dot 6080705 at redhat dot com>
On 10/17/2014 01:36 AM, Pedro Alves wrote:
> On 10/11/2014 07:39 AM, Jose E. Marchesi wrote:
>>
>> (gdb) info probes
>> Provider Name Where Semaphore Enabled Object
>> demo am-main 0x0000000000400c96 n/a /home/jemarch/oracle/usdt/demo
>> demo another 0x0000000000400c8b n/a always /home/jemarch/oracle/usdt/demo
>> demo progress-counter 0x0000000000400c81 n/a no /home/jemarch/oracle/usdt/demo
>>
>> In the example above demo:am-main is a systemtap probe, for which
>> "Enabled" reads n/a. demo:another is a dtrace probe which cannot be
>> disabled (it does not have any associated enabler) and
>> demo:progress-counter is a dtrace probe which is disabled.
>
> Shouldn't we explicitly say which probe is stap, vs dprobe (vs whatever
> other probe type)? Like, either a new column:
>
> ~~~
> Type Provider Name Where Semaphore Enabled Object
> stap demo am-main 0x0000000000400c96 n/a /home/jemarch/oracle/usdt/demo
> dtrace demo another 0x0000000000400c8b n/a always /home/jemarch/oracle/usdt/demo
> dtrace demo progress-counter 0x0000000000400c81 n/a no /home/jemarch/oracle/usdt/demo
> ~~~
>
> or, sort output by probe type:
>
> ~~~
> Stap probes:
>
> Type Provider Name Where Semaphore Enabled Object
> stap demo am-main 0x0000000000400c96 n/a /home/jemarch/oracle/usdt/demo
>
> Dtrace probes:
>
> Type Provider Name Where Semaphore Enabled Object
> dtrace demo another 0x0000000000400c8b n/a always /home/jemarch/oracle/usdt/demo
> dtrace demo progress-counter 0x0000000000400c81 n/a no /home/jemarch/oracle/usdt/demo
> ~~~
This also raises the question, can't we have both a stap
probe and a dtrace probe with the name provider and name? Like,
using the proposed output that doesn't distinguish the probe types,
can't the user end up with the confusing:
Provider Name Where Semaphore Enabled Object
demo am-main 0x0000000000400c96 n/a /home/jemarch/oracle/usdt/demo
demo am-main 0x0000000000400c8b n/a always /home/jemarch/oracle/usdt/demo
Does GDB cope correctly with this? Will the user have
trouble specifying the probe he wants with the current UI?
Thanks,
Pedro Alves