Re: [RFC PATCH v5 1/2] trace,smp: Add tracepoints around remotelly called functions

From: Valentin Schneider
Date: Thu Jun 15 2023 - 12:44:25 EST


On 15/06/23 03:59, Leonardo Bras wrote:
> The recently added ipi_send_{cpu,cpumask} tracepoints allow finding sources
> of IPIs targeting CPUs running latency-sensitive applications.
>
> For NOHZ_FULL CPUs, all IPIs are interference, and those tracepoints are
> sufficient to find them and work on getting rid of them. In some setups
> however, not *all* IPIs are to be suppressed, but long-running IPI
> callbacks can still be problematic.
>
> Add a pair of tracepoints to mark the start and end of processing a CSD IPI
> callback, similar to what exists for softirq, workqueue or timer callbacks.
>
> Signed-off-by: Leonardo Bras <leobras@xxxxxxxxxx>

Tested-and-reviewed-by: Valentin Schneider <vschneid@xxxxxxxxxx>