Re: [PATCH v4 05/12] perf record: start threads in the beginning of trace streaming

> + err = write(thread->pipes.ack[1], &msg, sizeof(msg)); > + if (err == -1) > + pr_err("threads[%d]: failed to notify on start. Error %m", > thread->tid); It might be safer to not use %m. I'm not sure if all the non glibc libcs that people use support it.

[PATCH v4 05/12] perf record: start threads in the beginning of trace streaming

Start thread in detached state because its management is implemented via messaging to avoid any scaling issues. Block signals prior thread start so only main tool thread would be notified on external async signals during data collection. Thread affinity mask is used to assign eligible cpus for th