Comment 16 for bug 1026926

I can also verify this on

[root@server:~]# yum list installed | grep percona
Percona-Server-client-55.x86_64 5.5.27-rel28.0.291.rhel6 @percona
Percona-Server-devel-55.x86_64 5.5.27-rel28.0.291.rhel6 @percona
Percona-Server-server-55.x86_64 5.5.27-rel28.0.291.rhel6 @percona
Percona-Server-shared-55.x86_64 5.5.27-rel28.0.291.rhel6 @percona
Percona-Server-test-55.x86_64 5.5.27-rel28.0.291.rhel6 @percona
percona-release.x86_64 0.0-1 installed
[root@server:~]# cat /etc/redhat-release
CentOS release 6.3 (Final)

=====================================
120829 2:04:35 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 49 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 39026 1_second, 39026 sleeps, 3901 10_second, 16 backgr ound, 16 flush
srv_master_thread log flush and writes: 41415
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 10132, signal count 16893
--Thread 139685146564352 has waited at buf0buf.c line 3667 for 251.00 seconds th e semaphore:
Mutex at 0x2dba8f8 '&buf_pool->mutex', lock var 1
waiters flag 1
--Thread 139685157054208 has waited at buf0flu.c line 1887 for 245.00 seconds th e semaphore:
Mutex at 0x2dba8f8 '&buf_pool->mutex', lock var 1
waiters flag 1
--Thread 139684885821184 has waited at buf0lru.c line 1102 for 237.00 seconds th e semaphore:
Mutex at 0x2dba8f8 '&buf_pool->mutex', lock var 1
waiters flag 1
Mutex spin waits 15906, rounds 125370, OS waits 3319
RW-shared spins 5150, rounds 122649, OS waits 4016
RW-excl spins 3970, rounds 94541, OS waits 2753
Spin rounds per wait: 7.88 mutex, 23.82 RW-shared, 23.81 RW-excl
--------
FILE I/O
--------
I/O thread 0 state: waiting for completed aio requests (insert buffer thread)
I/O thread 1 state: waiting for completed aio requests (log thread)
I/O thread 2 state: waiting for completed aio requests (read thread)
I/O thread 3 state: waiting for completed aio requests (read thread)
I/O thread 4 state: waiting for completed aio requests (read thread)
I/O thread 5 state: waiting for completed aio requests (read thread)
I/O thread 6 state: waiting for completed aio requests (write thread)
I/O thread 7 state: waiting for completed aio requests (write thread)
I/O thread 8 state: waiting for completed aio requests (write thread)
I/O thread 9 state: waiting for completed aio requests (write thread)
Pending normal aio reads: 0 [0, 0, 0, 0] , aio writes: 0 [0, 0, 0, 0] ,
 ibuf aio reads: 0, log i/o's: 0, sync i/o's: 0
Pending flushes (fsync) log: 0; buffer pool: 0
8013 OS file reads, 567592 OS file writes, 119812 OS fsyncs
0.00 reads/s, 0 avg bytes/read, 0.00 writes/s, 0.00 fsyncs/s
-------------------------------------
INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 27, seg size 29, 0 merges
merged operations:
 insert 0, delete mark 0, delete 0
discarded operations:
 insert 0, delete mark 0, delete 0
Hash table size 4425293, node heap has 23560 buffer(s)
0.00 hash searches/s, 0.00 non-hash searches/s
---
LOG
---
Log sequence number 25111636828
Log flushed up to 25111636496
Last checkpoint at 25063541159
Max checkpoint age 434154333
Checkpoint age target 420587011
Modified age 48095669
Checkpoint age 48095669
0 pending log writes, 0 pending chkp writes
88139 log i/o's done, 0.00 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total memory allocated 2206203904; in additional pool allocated 0
Internal hash tables (constant factor + variable factor)
    Adaptive hash index 421413600 (35402344 + 386011256)
    Page hash 2213656 (buffer pool 0 only)
    Dictionary cache 11266520 (8851984 + 2414536)
    File system 226552 (82672 + 143880)
    Lock system 5314664 (5313416 + 1248)
    Recovery system 0 (0 + 0)
Dictionary memory allocated 2414536
InnoDB: ###### Diagnostic info printed to the standard error stream
InnoDB: Warning: a long semaphore wait:
--Thread 139685146564352 has waited at buf0buf.c line 3667 for 272.00 seconds th e semaphore:
Mutex at 0x2dba8f8 '&buf_pool->mutex', lock var 1
waiters flag 1
InnoDB: Warning: a long semaphore wait:
--Thread 139685157054208 has waited at buf0flu.c line 1887 for 266.00 seconds th e semaphore:
Mutex at 0x2dba8f8 '&buf_pool->mutex', lock var 1
waiters flag 1
InnoDB: Warning: a long semaphore wait:
--Thread 139684885821184 has waited at buf0lru.c line 1102 for 258.00 seconds th e semaphore:
Mutex at 0x2dba8f8 '&buf_pool->mutex', lock var 1
waiters flag 1
InnoDB: ###### Starts InnoDB Monitor for 30 secs to print diagnostic info:
InnoDB: Pending preads 0, pwrites 0
InnoDB: ###### Diagnostic info printed to the standard error stream
InnoDB: Warning: a long semaphore wait:
--Thread 139685146564352 has waited at buf0buf.c line 3667 for 303.00 seconds th e semaphore:
Mutex at 0x2dba8f8 '&buf_pool->mutex', lock var 1
waiters flag 1
InnoDB: Warning: a long semaphore wait:
--Thread 139685157054208 has waited at buf0flu.c line 1887 for 297.00 seconds th e semaphore:
Mutex at 0x2dba8f8 '&buf_pool->mutex', lock var 1
waiters flag 1
InnoDB: Warning: a long semaphore wait:
--Thread 139684885821184 has waited at buf0lru.c line 1102 for 289.00 seconds th e semaphore:
Mutex at 0x2dba8f8 '&buf_pool->mutex', lock var 1
waiters flag 1
InnoDB: ###### Starts InnoDB Monitor for 30 secs to print diagnostic info:
InnoDB: Pending preads 0, pwrites 0
InnoDB: ###### Diagnostic info printed to the standard error stream