Speaker
Description
Debugging latency issues in production RT kernels often requires
understanding where and why preemption and interrupts are being
disabled. Today, enabling the preempt_disable/enable and
irq_disable/enable tracepoints requires pulling in heavyweight
infrastructure — either the preemptoff/irqsoff latency tracers or the
full lockdep IRQ tracking — that carries too much overhead for
production deployments. This forces engineers to reproduce customer
issues in lab environments, which is often impractical for intermittent
latency problems.
This talk presents a patch series that introduces
CONFIG_TRACE_PREEMPT_TOGGLE and CONFIG_TRACE_IRQFLAGS_TOGGLE, two
new user-selectable kernel options that enable these tracepoints
independently, with minimal overhead. The tracepoints are gated behind
static keys.