[lttng-dev] PERF PARAMETERS

[Julien Desfossez]

Hi,

On 14-08-26 11:21 PM, Jessica Foest wrote:
> Hi 
> 
> i tried to retrieve system calls traces with all perf context parameters
> . the problem is that only a few PERF counters are activated and lttng
> fails to activate  the other perf context parameters.
> how can i solve it ?

There is a hardware limit on the number perf PMU counters that can be
activated at the same time. It depends on the CPU and if you are on a
virtual machine.
If I remember correctly it is 3 or 4 on the i7.

Julien