Hi Masami, thanks for looking at this.
On Tue, 9 Jan 2024 22:04:45 +0900 Masami Hiramatsu (Google) <mhira...@kernel.org> wrote: > > The tracing ring-buffers can be stored on disk or sent to network > > without any copy via splice. However the later doesn't allow real time > > processing of the traces. A solution is to give userspace direct access > > to the ring-buffer pages via a mapping. An application can now become a > > consumer of the ring-buffer, in a similar fashion to what trace_pipe > > offers. > > I think this is very nice feature. But this series seems just a feature, > no document and no example code. Can you add 2 patches to add those? > I know libtracefs already provide a support code, but I think it is > better to have a test code under tools/testing/selftests/ring_buffer. Yeah, we should have sample code and a test. > > I also wonder what happen if other operation (e.g. taking snapshot) happens > while mmaping the ring buffer. Hmm, good point. We should disable snapshots when mapped, and also prevent mapping with latency tracer if we are not already doing that. -- Steve
