[Samba] Samba4 consumes more CPU

Andrew Bartlett abartlet at samba.org
Wed Aug 28 17:00:29 MDT 2013

On Mon, 2013-08-26 at 22:39 +0530, Prema wrote:
> Dear Andrew,
> As per your suggestion , I have attached the gdb log of the samba and
> smbd process log running in the single server mode.
> Also when I noted in the perf top, libndr.so consumes the maximum cpu.

> I noticed that it happens soon after sometime the samba process is
> started and the CPU is filled up.
> Since the samba process occupies 100% atleast two or more CPUs out of
> 8 CPU , the clients are not able to get authenticate to the server.
> Kindly go through the logs and suggest what can be done to lessen the
> CPU consumption.

Sadly the gdb backtrace does not happen to be from the point that is
consuming the CPU, if that really is in libndr.  It is in both cases in
a poll() loop.

Are you using the internal DNS server?  If so, please change to using
DLZ_BIND9 using the samba_upgradedns script, and see if that helps.  I
have had a more successful investigation with another user that
indicates an issue there, trigged by double-processing of secure DNS
updates from clients in our DNS server.


Andrew Bartlett

Andrew Bartlett
Authentication Developer, Samba Team           http://samba.org
Samba Developer, Catalyst IT                   http://catalyst.net.nz

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