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authorOlaf Kirch <okir@suse.de>2006-12-01 10:39:12 +0100
committerJens Axboe <jens.axboe@oracle.com>2006-12-01 10:39:12 +0100
commitbe1c63411addba3ad750eb4fdfc50b97bc82825e (patch)
treed00c889873310a5c6ee0caf79f2b70e64a382796 /block
parent0215ffb08ce99e2bb59eca114a99499a4d06e704 (diff)
downloadlinux-linaro-stable-be1c63411addba3ad750eb4fdfc50b97bc82825e.tar.gz
[PATCH] blktrace: add timestamp message
This adds a new timestamp message to blktrace, giving the timeofday when we starting tracing. This helps user space correlate block trace events with eg an application strace. This requires a (compatible) update to blkparse. The changed blkparse is still able to process traces generated by older kernels, and older versions of blkparse should silently ignore the new records (because they have a pid of 0). Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
-rw-r--r--block/blktrace.c57
1 files changed, 45 insertions, 12 deletions
diff --git a/block/blktrace.c b/block/blktrace.c
index 135593c8e45b..562ca7cbf858 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -22,30 +22,61 @@
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/debugfs.h>
+#include <linux/time.h>
#include <asm/uaccess.h>
static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, };
static unsigned int blktrace_seq __read_mostly = 1;
/*
+ * Send out a notify message.
+ */
+static inline unsigned int trace_note(struct blk_trace *bt,
+ pid_t pid, int action,
+ const void *data, size_t len)
+{
+ struct blk_io_trace *t;
+ int cpu = smp_processor_id();
+
+ t = relay_reserve(bt->rchan, sizeof(*t) + len);
+ if (t == NULL)
+ return 0;
+
+ t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
+ t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
+ t->device = bt->dev;
+ t->action = action;
+ t->pid = pid;
+ t->cpu = cpu;
+ t->pdu_len = len;
+ memcpy((void *) t + sizeof(*t), data, len);
+ return blktrace_seq;
+}
+
+/*
* Send out a notify for this process, if we haven't done so since a trace
* started
*/
static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
{
- struct blk_io_trace *t;
+ tsk->btrace_seq = trace_note(bt, tsk->pid,
+ BLK_TN_PROCESS,
+ tsk->comm, sizeof(tsk->comm));
+}
- t = relay_reserve(bt->rchan, sizeof(*t) + sizeof(tsk->comm));
- if (t) {
- t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
- t->device = bt->dev;
- t->action = BLK_TC_ACT(BLK_TC_NOTIFY);
- t->pid = tsk->pid;
- t->cpu = smp_processor_id();
- t->pdu_len = sizeof(tsk->comm);
- memcpy((void *) t + sizeof(*t), tsk->comm, t->pdu_len);
- tsk->btrace_seq = blktrace_seq;
- }
+static void trace_note_time(struct blk_trace *bt)
+{
+ struct timespec now;
+ unsigned long flags;
+ u32 words[2];
+
+ getnstimeofday(&now);
+ words[0] = now.tv_sec;
+ words[1] = now.tv_nsec;
+
+ local_irq_save(flags);
+ trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
+ local_irq_restore(flags);
}
static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
@@ -394,6 +425,8 @@ static int blk_trace_startstop(request_queue_t *q, int start)
blktrace_seq++;
smp_mb();
bt->trace_state = Blktrace_running;
+
+ trace_note_time(bt);
ret = 0;
}
} else {