jbd2: jbd2 stats through procfs
The patch below updates the jbd stats patch to 2.6.20/jbd2.
The initial patch was posted by Alex Tomas in December 2005
(http://marc.info/?l=linux-ext4&m=113538565128617&w=2).
It provides statistics via procfs such as transaction lifetime and size.
Sometimes, investigating performance problems, i find useful to have
stats from jbd about transaction's lifetime, size, etc. here is a
patch for review and inclusion probably.
for example, stats after creation of 3M files in htree directory:
[root@bob ~]# cat /proc/fs/jbd/sda/history
R/C tid wait run lock flush log hndls block inlog ctime write drop close
R 261 8260 2720 0 0 750 9892 8170 8187
C 259 750 0 4885 1
R 262 20 2200 10 0 770 9836 8170 8187
R 263 30 2200 10 0 3070 9812 8170 8187
R 264 0 5000 10 0 1340 0 0 0
C 261 8240 3212 4957 0
R 265 8260 1470 0 0 4640 9854 8170 8187
R 266 0 5000 10 0 1460 0 0 0
C 262 8210 2989 4868 0
R 267 8230 1490 10 0 4440 9875 8171 8188
R 268 0 5000 10 0 1260 0 0 0
C 263 7710 2937 4908 0
R 269 7730 1470 10 0 3330 9841 8170 8187
R 270 0 5000 10 0 830 0 0 0
C 265 8140 3234 4898 0
C 267 720 0 4849 1
R 271 8630 2740 20 0 740 9819 8170 8187
C 269 800 0 4214 1
R 272 40 2170 10 0 830 9716 8170 8187
R 273 40 2280 0 0 3530 9799 8170 8187
R 274 0 5000 10 0 990 0 0 0
where,
R - line for transaction's life from T_RUNNING to T_FINISHED
C - line for transaction's checkpointing
tid - transaction's id
wait - for how long we were waiting for new transaction to start
(the longest period journal_start() took in this transaction)
run - real transaction's lifetime (from T_RUNNING to T_LOCKED
lock - how long we were waiting for all handles to close
(time the transaction was in T_LOCKED)
flush - how long it took to flush all data (data=ordered)
log - how long it took to write the transaction to the log
hndls - how many handles got to the transaction
block - how many blocks got to the transaction
inlog - how many blocks are written to the log (block + descriptors)
ctime - how long it took to checkpoint the transaction
write - how many blocks have been written during checkpointing
drop - how many blocks have been dropped during checkpointing
close - how many running transactions have been closed to checkpoint this one
all times are in msec.
[root@bob ~]# cat /proc/fs/jbd/sda/info
280 transaction, each upto 8192 blocks
average:
1633ms waiting for transaction
3616ms running transaction
5ms transaction was being locked
1ms flushing data (in ordered mode)
1799ms logging transaction
11781 handles per transaction
5629 blocks per transaction
5641 logged blocks per transaction
Signed-off-by: Johann Lombardi <johann.lombardi@bull.net>
Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index d861ffd..6856400 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -395,6 +395,16 @@
};
+/*
+ * Some stats for checkpoint phase
+ */
+struct transaction_chp_stats_s {
+ unsigned long cs_chp_time;
+ unsigned long cs_forced_to_close;
+ unsigned long cs_written;
+ unsigned long cs_dropped;
+};
+
/* The transaction_t type is the guts of the journaling mechanism. It
* tracks a compound transaction through its various states:
*
@@ -532,6 +542,21 @@
spinlock_t t_handle_lock;
/*
+ * Longest time some handle had to wait for running transaction
+ */
+ unsigned long t_max_wait;
+
+ /*
+ * When transaction started
+ */
+ unsigned long t_start;
+
+ /*
+ * Checkpointing stats [j_checkpoint_sem]
+ */
+ struct transaction_chp_stats_s t_chp_stats;
+
+ /*
* Number of outstanding updates running on this transaction
* [t_handle_lock]
*/
@@ -562,6 +587,39 @@
};
+struct transaction_run_stats_s {
+ unsigned long rs_wait;
+ unsigned long rs_running;
+ unsigned long rs_locked;
+ unsigned long rs_flushing;
+ unsigned long rs_logging;
+
+ unsigned long rs_handle_count;
+ unsigned long rs_blocks;
+ unsigned long rs_blocks_logged;
+};
+
+struct transaction_stats_s {
+ int ts_type;
+ unsigned long ts_tid;
+ union {
+ struct transaction_run_stats_s run;
+ struct transaction_chp_stats_s chp;
+ } u;
+};
+
+#define JBD2_STATS_RUN 1
+#define JBD2_STATS_CHECKPOINT 2
+
+static inline unsigned long
+jbd2_time_diff(unsigned long start, unsigned long end)
+{
+ if (end >= start)
+ return end - start;
+
+ return end + (MAX_JIFFY_OFFSET - start);
+}
+
/**
* struct journal_s - The journal_s type is the concrete type associated with
* journal_t.
@@ -623,6 +681,12 @@
* @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the
* number that will fit in j_blocksize
* @j_last_sync_writer: most recent pid which did a synchronous write
+ * @j_history: Buffer storing the transactions statistics history
+ * @j_history_max: Maximum number of transactions in the statistics history
+ * @j_history_cur: Current number of transactions in the statistics history
+ * @j_history_lock: Protect the transactions statistics history
+ * @j_proc_entry: procfs entry for the jbd statistics directory
+ * @j_stats: Overall statistics
* @j_private: An opaque pointer to fs-private information.
*/
@@ -815,6 +879,19 @@
pid_t j_last_sync_writer;
/*
+ * Journal statistics
+ */
+ struct transaction_stats_s *j_history;
+ int j_history_max;
+ int j_history_cur;
+ /*
+ * Protect the transactions statistics history
+ */
+ spinlock_t j_history_lock;
+ struct proc_dir_entry *j_proc_entry;
+ struct transaction_stats_s j_stats;
+
+ /*
* An opaque pointer to fs-private information. ext3 puts its
* superblock pointer here
*/