On Fri, 16 May 2025 16:39:56 -0700 Namhyung Kim <namhy...@kernel.org> wrote:
> Hi Steve, > > On Wed, May 14, 2025 at 01:27:20PM -0400, Steven Rostedt wrote: > > On Tue, 13 May 2025 18:34:35 -0400 > > Steven Rostedt <rost...@goodmis.org> wrote: > > > > > This has modifications in x86 and I would like it to go through the x86 > > > tree. Preferably it can go into this merge window so we can focus on > > > getting > > > perf and ftrace to work on top of this. > > > > I think it may be best for me to remove the two x86 specific patches, and > > rebuild the ftrace work on top of it. For testing, I'll just keep those two > > patches in my tree locally, but then I can get this moving for this merge > > window. > > Maybe I asked this before but I don't remember if I got the answer. :) > How does it handle task exits as it won't go to userspace? I guess it'll > lose user callstacks for exit syscalls and other termination paths. > > Similarly, it will miss user callstacks in the samples at the end of > profiling if the target tasks remain in the kernel (or they sleep). > It looks like a fundamental limitation of the deferred callchains. Can we use a hybrid approach for this case? It might be more balanced (from the performance point of view) to save the full stack in a classic way only in this case, rather than faulting on process exit or doing file access just to load the sframe. Thanks, > > Thanks, > Namhyung > > > > > Next merge window, we can spend more time on getting the perf API working > > properly. > > > > -- Steve -- Masami Hiramatsu (Google) <mhira...@kernel.org>
