Messages in this thread Patch in this message | | | Date | Mon, 2 Feb 2009 20:30:40 -0200 | From | Arnaldo Carvalho de Melo <> | Subject | [PATCH tip 3/3] blkftrace: binary tracing, synthesizing old format |
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Impact: new feature
With this and a blkrawverify modified not to verify the sequence numbers we can start using the userspace tools to verify that the data produced with the ftrace plugin works as expected.
Example:
[root@f10-1 ~]# echo 1 > /sys/block/sda/sda1/trace/enable [root@f10-1 ~]# echo bin > /d/tracing/trace_options [root@f10-1 ~]# echo blk > /d/tracing/current_tracer [root@f10-1 ~]# cat /d/tracing/trace_pipe > sda1.blktrace.0 ^C [root@f10-1 ~]# ./blkrawverify --noseq sda1 Verifying sda1 CPU 0 Wrote output to sda1.verify.out [root@f10-1 ~]# cat sda1.verify.out
--------------- Verifying sda1 --------------------- Summary for cpu 0: 1349 valid + 0 invalid (100.0%) processed
[root@f10-1 ~]#
Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- block/blktrace.c | 40 +++++++++++++++++++++++++++++++++++++--- 1 files changed, 37 insertions(+), 3 deletions(-)
diff --git a/block/blktrace.c b/block/blktrace.c index 570cd3c..4f45b34 100644 --- a/block/blktrace.c +++ b/block/blktrace.c @@ -219,9 +219,16 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; t->sequence = ++(*sequence); t->time = ktime_to_ns(ktime_get()); - t->cpu = cpu; - t->pid = pid; record_it: + /* + * These two are not needed in ftrace as they are in the + * generic trace_entry, filled by tracing_generic_entry_update, + * but for the trace_event->bin() synthesizer benefit we do it + * here too. + */ + t->cpu = cpu; + t->pid = pid; + t->sector = sector; t->bytes = bytes; t->action = what; @@ -1086,6 +1093,7 @@ static void blk_tracer_start(struct trace_array *tr) if (blk_register_tracepoints()) atomic_dec(&blk_probes_ref); mutex_unlock(&blk_probe_mutex); + trace_flags &= ~TRACE_ITER_CONTEXT_INFO; } static int blk_tracer_init(struct trace_array *tr) @@ -1100,6 +1108,7 @@ static int blk_tracer_init(struct trace_array *tr) static void blk_tracer_stop(struct trace_array *tr) { + trace_flags |= TRACE_ITER_CONTEXT_INFO; mutex_lock(&blk_probe_mutex); if (atomic_dec_and_test(&blk_probes_ref)) blk_unregister_tracepoints(); @@ -1147,6 +1156,9 @@ static int blk_trace_event_print(struct trace_iterator *iter, int flags) const u16 what = t->action & ((1 << BLK_TC_SHIFT) - 1); int ret; + if (trace_print_context(iter)) + return TRACE_TYPE_PARTIAL_LINE; + if (unlikely(what == 0 || what > ARRAY_SIZE(what2act))) ret = trace_seq_printf(s, "Bad pc action %x\n", what); else { @@ -1159,6 +1171,28 @@ static int blk_trace_event_print(struct trace_iterator *iter, int flags) return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; } +static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) +{ + struct trace_seq *s = &iter->seq; + struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; + const int offset = offsetof(struct blk_io_trace, sector); + struct blk_io_trace old = { + .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, + .time = ns2usecs(iter->ts), + }; + + if (!trace_seq_putmem(s, &old, offset)) + return 0; + return trace_seq_putmem(s, &t->sector, + sizeof(old) - offset + t->pdu_len); +} + +static int blk_trace_event_print_binary(struct trace_iterator *iter, int flags) +{ + return blk_trace_synthesize_old_trace(iter) ? + TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; +} + static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) { const struct blk_io_trace *t; @@ -1200,7 +1234,7 @@ static struct trace_event trace_blk_event = { .latency_trace = blk_trace_event_print, .raw = trace_nop_print, .hex = trace_nop_print, - .binary = trace_nop_print, + .binary = blk_trace_event_print_binary, }; static int __init init_blk_tracer(void) -- 1.6.0.6
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