Re: [PATCH v5] tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast

From: Alexei Starovoitov

Date: Fri Jan 09 2026 - 16:54:46 EST


On Fri, Jan 9, 2026 at 12:21 PM Mathieu Desnoyers
<mathieu.desnoyers@xxxxxxxxxxxx> wrote:
>
>
> * preempt disable/enable pair: 1.1 ns
> * srcu-fast lock/unlock: 1.5 ns
>
> CONFIG_RCU_REF_SCALE_TEST=y
> * migrate disable/enable pair: 3.0 ns

.. and you're arguing that 3ns vs 1ns difference is so important
for your out-of-tree tracer that in-tree tracers need to do
some workarounds?! wtf