PATCH: Add DTrace probes

[Paul van den Bogaard]

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 <Trond.Norbye at Sun.COM> 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                                
Paul.vandenBogaard at sun.com
ISV-E  -- ISV Engineering, Opensource Engineering group

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