Bug#672675: mysql-server-core-5.5: frequent wake-ups while idle

2012-05-12 Thread Piotr Engelking 
Package: mysql-server-core-5.5
Version: 5.5.23-2
Severity: normal

The MySQL server wakes up several times per second even if no clients
are connected. Waking up the CPU unnecessarily results in increased
power consumption. Please consider allowing mysqld to sleep until it
has queries to process.

Here is the result of tracing all threads of idle mysqld for 4 seconds:

# for i in /proc/$(pidof mysqld)/task/*; do timeout -s INT 4 strace -p
$(basename $i); done
Process 11711 attached - interrupt to quit
restart_syscall(<... resuming interrupted call ...> 
Process 11711 detached
Process 11731 attached - interrupt to quit
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256,  
Process 11731 detached
Process 11732 attached - interrupt to quit
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256,  
Process 11732 detached
Process 11733 attached - interrupt to quit
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256,  
Process 11733 detached
Process 11734 attached - interrupt to quit
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256,  
Process 11734 detached
Process 11735 attached - interrupt to quit
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256,  
Process 11735 detached
Process 11736 attached - interrupt to quit
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256,  
Process 11736 detached
Process 11737 attached - interrupt to quit
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256,  
Process 11737 detached
Process 11738 attached - interrupt to quit
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256,  
Process 11738 detached
Process 11739 attached - interrupt to quit
io_getevents(-202637312, 1, 256, {}{0, 5}) = 0
io_getevents(-202637312, 1, 256, {}{0, 5}) = 0
io_getevents(-202637312, 1, 256, {}{0, 5}) = 0
io_getevents(-202637312, 1, 256, {}{0, 5}) = 0
io_getevents(-202637312, 1, 256, {}{0, 50

Bug#672675: [debian-mysql] Bug#672675: mysql-server-core-5.5: frequent wake-ups while idle

2012-05-13 Thread Nicholas Bamber 

Piotr,
	As described in 
http://dev.mysql.com/doc/innodb/1.1/en/innodb-performance-aio-linux.html, you 
can set "innodb_use_native_aio=0" in the [mysqld] section of the config 
file.


	I hope this helps. I'll put your question up on the FAQ 
(http://wiki.debian.org/Teams/MySQL/FAQ) and close the report if you 
have no other issues.



On 12/05/12 19:54, Piotr Engelking wrote:

Package: mysql-server-core-5.5
Version: 5.5.23-2
Severity: normal

The MySQL server wakes up several times per second even if no clients
are connected. Waking up the CPU unnecessarily results in increased
power consumption. Please consider allowing mysqld to sleep until it
has queries to process.

Here is the result of tracing all threads of idle mysqld for 4 seconds:

# for i in /proc/$(pidof mysqld)/task/*; do timeout -s INT 4 strace -p
$(basename $i); done
Process 11711 attached - interrupt to quit
restart_syscall(<... resuming interrupted call ...>  
Process 11711 detached
Process 11731 attached - interrupt to quit
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256, {}{0, 5}) = 0
io_getevents(-202268672, 1, 256,
Process 11731 detached
Process 11732 attached - interrupt to quit
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256, {}{0, 5}) = 0
io_getevents(-202280960, 1, 256,
Process 11732 detached
Process 11733 attached - interrupt to quit
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256, {}{0, 5}) = 0
io_getevents(-202428416, 1, 256,
Process 11733 detached
Process 11734 attached - interrupt to quit
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256, {}{0, 5}) = 0
io_getevents(-202440704, 1, 256,
Process 11734 detached
Process 11735 attached - interrupt to quit
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256, {}{0, 5}) = 0
io_getevents(-202452992, 1, 256,
Process 11735 detached
Process 11736 attached - interrupt to quit
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256, {}{0, 5}) = 0
io_getevents(-202465280, 1, 256,
Process 11736 detached
Process 11737 attached - interrupt to quit
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256, {}{0, 5}) = 0
io_getevents(-202612736, 1, 256,
Process 11737 detached
Process 11738 attached - interrupt to quit
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) = 0
io_getevents(-202625024, 1, 256, {}{0, 5}) =