[AGENT++] SNMP v3 get performance

[John McCaskey]

Hi Frank,

It does look that way, there is an SNMP->engine_id_discovery() function, but
perhaps I will send the request the way I am already doing it the first time
around, discover the engine id off the response, and then after that keep
the engine id around for use adding localized users for future requests to
the same device.  Thanks for your help.

John

On 3/20/06, Frank Fock <fock at agentpp.com> wrote:
>
> Hi John,
>
> You can discovered the engine ID by sending a single
> SNMPv3 PDU. I think SNMP++ already provides such a
> function.
>
> Frank
>
> John McCaskey wrote:
> > 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 <mailto: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.
> >      > _______________________________________________
> >      > AGENTPP mailing list
> >      > AGENTPP at agentpp.org <mailto:AGENTPP at agentpp.org>
> >      > http://lists.agentpp.org/mailman/listinfo/agentpp
> >
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> >
> >
>
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