[AGENT++] SNMP v3 get performance

[John McCaskey]

Hi Frank,

Thanks for the response.  The only issue I see with your approach is that I
don't know the remote agents engine IDs.  If I try to go with that approach
is there a good efficient way to discover the engine IDs as well, or will I
need to gather and know them upfront if I'm to achieve good performance?

John

On 3/20/06, Frank Fock <fock at agentpp.com> wrote:
>
> Hi John,
>
> I think adding localized users only will provide
> best performance. As you know the user/passphrase
> combination for all agents, you can localize them
> with the agent's engine IDs and add them all to
> the USM before you start polling. After that, you
> do not need to modify the USM anymore.
>
> Best regards,
> Frank
>
> John McCaskey wrote:
> > Everyone,
> >
> > Using the patch I previously provided for per session v3MP objects I
> have my
> > polling engine running and stable using SNMP++ for all of our SNMP
> > requests.  I have 80 threads that get spawned, each create's it's own
> v3MP
> > object, and each checks a global queue for devices that need SNMP
> polling.
> > Each thread then once it has a device sets up a new snmp session, which
> > includes doing a usm->add_usm_user() call if the device is using v3, and
> > then issues SNMP get requests on groups of OIDs until it has gathered
> all
> > the data needed for the device.
> >
> > This works well, but the performance when polling a large number of v3
> > devices is pretty bad.  For v1 I can poll several thousand devices in a
> > matter of a minute or two and performance is quite good on par with
> Net-SNMP
> > which we used previously.  However, if I have just a couple hundred v3
> > devices the performance starts to crawl.  Under my linux build I've been
> > using oprofile to gather some performance data and it seems that the
> bulk of
> > the time is being spent in the MD5 routines, I'm testing with a security
> > level of authPriv using MD5/DES.  Here is the output from oprofile:
> >
> > CPU: P4 / Xeon with 2 hyper-threads, speed 2592.35 MHz (estimated)
> > Counted GLOBAL_POWER_EVENTS events (time during which processor is not
> > stopped) with a unit mask of 0x01 (mandatory) count 100000
> > samples % linenr info symbol name
> > 9306146 64.4420 md5c.cpp:220 MD5Transform
> > 3414196 23.6422 auth_priv.cpp:1040 AuthMD5::password_to_key(unsigned
> char
> > const*, unsigned int, unsigned char const*, un
> > signed int, unsigned char*, unsigned int*)
> > 821898 5.6914 md5c.cpp:332 Decode
> >
> > I'm interested in any suggestions on cutting down this time.  I know
> Jochen
> > already mentioned that I shouldn't keep calling add_usm_user if the user
> has
> > already been added previously, but given that each device may have any
> > user/password combination and I have no way of knowing whether a device
> may
> > use the same username as another, but have a different password I don't
> see
> > how I can avoid that.  It seems like maybe what I need is for the table
> of
> > added users inside snmp++ to be a little smarter and not lookup by just
> > username but also by password so that whenever I add it will reuse if an
> > exact match exists otherwise add the user again and perform the MD5
> > computations again.  Does that seem like the best approach to improving
> > performance?
> >
> > John McCaskey
> > Klir Technologies, Inc.
> > _______________________________________________
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> > AGENTPP at agentpp.org
> > http://lists.agentpp.org/mailman/listinfo/agentpp
>
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