Samba and Application Response Measurement (ARM 4.0)
davecb at sun.com
Sun Mar 23 22:27:16 GMT 2008
You want to look at your OS's code for time measurement: at
least two free OSs implement something like gethrtime() as
a call which does an entry/ring-crossing, reads one hardware
register and returns. Others do a full system call (:-()
My leaky memory says Linux is one of the fast ones, but
it's architecture dependant, too...
[On sparc it's a sequence of trap, shift left, or]
James Peach wrote:
> On 23/03/2008, Sven Kubiak <sk at it23.de> wrote:
>>After looking at all (well, most of) the "PROFILE stuff" i think this is the
>> best way to implment the monitoring we are looking for. From the measuring
>> point of view, the profiling does the same as ARM. The only difference is
>> that we want to break down measuring into a set of calls, e.g. a specific
>> client which is mounting a network drive as one "transaction". As i see it,
>> Samba profiling counts and measures the specific smb commands in total.
>> Please correct me, if i am wrong.
>> Unfortunatly i didn't get the profiling to work, yet. I used the
>> configuration option --with-profile and enabled profiling using smbcontrol,
>> but didn't find any output so far. Does the profiling uses a seperate
>> logfile or do i have to setup a monitor like pcp? Is the pcp example coming
>> with Samba 3 still up to date?
> No, the PCP PMDA in the Samba3 tree has bitrotted substantially.
> There is a new PMDA in this svn branch:
> This PMDA exports the metrics from the profile subsystem, and well as
> extra per-client and per-share counters. It should be straight-forward
> to extend it.
>> I found and old release note for Samba 2.2.1, which mentioned that the
>> profile collection degradation was about 8.5%.
> If you are just counting events, then last time I measured it the
> impact was negligible. The impact of measuring response times is
> significantly more, and depends on the timing facilities of the OS.
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