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>


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ISV-E  -- ISV Engineering, Opensource Engineering group

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