Jose R. Santos wrote: > On Mon, 11 Aug 2008 15:18:07 -0500 > Eric Sandeen <sandeen@xxxxxxxxxx> wrote: > >> As just an initial inquiry, I'm wondering how people would feel about >> putting some tracepoints (trace_mark()) into ext[34] for monitoring the >> fs behavior. >> >> Good/bad/indifferent? >> >> Thanks, >> >> -Eric > > Good idea, although Im not sure if ext[34] is the best place we should > start putting markers though. Sure, but there have already been patches floated for the vfs, and ... > For ext[34], I would start by putting markers on VFS entry points into > ext4 and journal activity. For these to be useful though, we also need > markers in the following places: > > iochedulers > elv_next_request() > elv_add_request() > elv_completed_request() I think there's talk of changing the blktrace infrastructure to use markers. > scsi > scsi_prep_fn() > scsi_dispatch_cmd() > scsi_done() > scsi_io_completion() > > Entry and exit points of all IO system calls. > AND > The VFS call for these system calls. http://lists-archives.org/linux-kernel/16489694-lttng-tracepoint-instrumentation-fs.html > bio > generic_make_request() > bio_endio() > > Scheduler > idle_balance() Personally, I find it useful to know when a > machine goes idle because is stalling on IO > > > Im sure Im missing something but this should be a good start to be able > to track the life of a pending IO to see where deficiencies lie. Yep, this all sounds good. Thanks, -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
