Well, I hoped it would spur some more clever ideas...
I thought it could be useful if you have some problems with your
application, and can use dtrace to track what operations are actually
performed on one particular key.
But aggregations may probably be more interesting.
Roy
Paul van den Bogaard wrote:
Mmm, I think that if copyinstr(arg1) == '1234..." that your trace output
will be rather dull :-)
--Paul
On 7-mrt-2008, at 14:37, Roy Lyseng wrote:
Another, slightly more advanced script is memcached-keytrace.d:
:memcached::command-set,command-add,command-delete,command-get
/pid == $target && copyinstr(arg1) == "123456789"/
{
trace(copyinstr(arg1));
}
END
{
}
This one will trace set, add, delete and get commands applied to one
specific key:
Invoke as:
dtrace -s ~/memcached/dtrace/memcached-trace.d -p 24167
Then run a telnet session:
telnet system 11211
Trying 9.9.9.9...
Connected to system.
Escape character is '^]'.
abcdefghij
ERROR
set 123456789 0 0 10
abcdefghij
STORED
delete 123456789 0 0
DELETED
get 123456789 0 0 0
END
And the dtrace script reports:
CPU ID FUNCTION:NAME
1 54165 complete_nread:command-set 123456789
0 54159 process_delete_command:command-delete 123456789
1 54160 process_get_command:command-get 123456789
Useful? Maybe...
Roy
Dustin Sallings wrote:
For those of us who haven't truly unleashed the power of dtrace,
can you describe the kinds of things we can learn from this (perhaps
with scripts)?
--Dustin Sallings (mobile)
On Mar 6, 2008, at 4:48, Trond Norbye <[EMAIL PROTECTED]> wrote:
On Mar 5, 2008, at 3:52 PM, Trond Norbye wrote:
The following patch adds a new configure-option (--enable-dtrace)
that adds DTrace probes to various parts of memcached.
Please comment.
Trond
I discovered that I had some "leftovers" in this patch from before I
fixed the comments regarding the large page support..
The attached version is replacement for the original patch.
Trond
<dtrace.patch.gz>
---------------------------------------------------------------------------------------------
Paul van den Bogaard
[EMAIL PROTECTED]
ISV-E -- ISV Engineering, Opensource Engineering group
Sun Microsystems, Inc phone: +31 334
515 918
Saturnus 1 extentsion: x
(70)15918
3824 ME Amersfoort mobile: +31 651
913 354
The Netherlands fax:
+31 334 515 001
