[Bug 86471] drastic reduction of write performance after the termination of mysqld

[bugzilla-daemon@bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=86471

--- Comment #2 from Markus Königshaus <m.koenigshaus@wut.de> ---
Hi Theodore,

even after a very long wait, the performance remain so low. The performance is
also low when you copy files. I have used dd, so I create only reproducible
write access.
I have now tested the ext3 FS, same result.

After some debugging I found out, there is a delay in start_this_handle (look
at the timing), with echo 5 > /sys/kernel/debug/jbd/jbd-debug I get:

>> before mysqlshutdown:
...
[   40.400755] fs/jbd/transaction.c: (journal_stop, 1380): h_ref 2 -> 1
[   40.400755] 
[   40.400765] fs/jbd/transaction.c: (journal_stop, 1384): Handle df03e000
going down
[   40.400765] 
[   40.400789] fs/jbd/transaction.c: (journal_start, 290): from journal_start
[   40.400789] 
[   40.400801] fs/jbd/transaction.c: (start_this_handle, 110): New handle
df03e000 going live.
[   40.400801] 
[   40.400813] fs/jbd/transaction.c: (start_this_handle, 229): Handle df03e000
given 14 credits (total 21, free 14286)
...

>> after mysqlshutdown:
...
[   61.383886] fs/jbd/transaction.c: (journal_stop, 1380): h_ref 2 -> 1
[   61.383886] 
[   61.383896] fs/jbd/transaction.c: (journal_stop, 1384): Handle df03e000
going down
[   61.383896] 
[   61.393528] fs/jbd/transaction.c: (start_this_handle, 110): New handle
df03e000 going live.
[   61.393528] 
[   61.393541] fs/jbd/transaction.c: (start_this_handle, 229): Handle df03e000
given 14 credits (total 21, free 14271)
...

I try to isolate the problem in more detail next week, I would welcome tips and
help for my try.

Regards, Markus

-- 
You are receiving this mail because:
You are watching the assignee of the bug.--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html