Re: gdb show thread names

On 13/06/2020 13:47, Philippe Waroquiers wrote:
> One year ago, I started a patch to add Ada task names and thread names.
> At the end, the patch for Ada task name went in, but for the thread
> names, there were still some work to do e.g. it was unclear how to
> properly give the thread name in some cases and/or 
> have a consistent presentation of the thread name.
> 
> The (partial) patch was giving a behaviour so that we e.g. get:
>       [New Thread 0x7ffff701b700 (LWP 13891) "sleepers"]
>       [Switching to thread 2 (Thread 0x7ffff781c700 (LWP 13890) "sleepers")]
>     instead of:
>       [New Thread 0x7ffff701b700 (LWP 13918)]
>       [Switching to thread 2 (Thread 0x7ffff781c700 (LWP 13917))]
> 
> Philippe
> 
> On Sat, 2020-06-13 at 01:16 +0100, Jonny Grant wrote:
>> Hello
>> Just wondering if gdb could show the thread names as they are created and deleted?
>>
>>
>> [Thread 0x7fff695e9700 (LWP 3580240) exited]
>> [New Thread 0x7fff98ff9700 (LWP 3580609)]
>>
>> $ cat /proc/3580609/comm
>> ThreadPoolForeg
>>
>> Could be a race condition, if GDB showed the name, before it was renamed by the application, but still pretty useful to see the names.
>>
>> If I break, and type "info thread" I can see those still created.
>>
>> Jonny
> 

Hi Philippe

That looks useful. Is "sleepers" the entrypoint symbol name?

I can see it is tricky because a thread may not have been named by something like pthread_setname_np() if /proc/3580609/comm is read immediately by gdb before the name could be set.

Jonny