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. 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() 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. 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. -JRS -- 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
