[lttng-dev] lttng snapshots and running traces

[Julien Desfossez]

On 13-09-26 02:20 PM, Thibault, Daniel wrote:
> Date: Thu, 26 Sep 2013 12:16:29 -0400
> From: Julien Desfossez <jdesfossez at efficios.com>
> 
>> When the consumer needs to read a subbuffer, it performs a get_subbuf operation. If this operation succeeds, 
>> the consumer has exclusive access to this subbuffer and so it can read it safely. If it fails, it means the tracer is 
>> currently using it and in the case of snapshots, the consumer will just skip to the next one (up to the end 
>> position it defined at the beginning of the snapshot).
>>
>> Julien
> 
>    Presumably the tracers also use get_subbuf, so what happens if they are refused access because the consumer 
> got the sub-buffer first?  Do they wait for the consumer to relinquish the sub-buffer, or do they skip ahead?
They skip ahead.

Julien

> 
> Daniel U. Thibault
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