descriptor_add going through password_hash_add and both takes a long time

Nadezhda Ivanova nivanova at
Mon May 25 03:36:53 MDT 2015

Hi Matthew,
Are you sure this is not just a single add request that creates a
user, going through the module stack? descriptor_add is in no way
invoking password_hash_add as a function, it is not spawning
additional add requests, and it is also above password_hash in the
list. In this case, yes, sorry, but this is intended - we are creating
a new object and it's SD has to be calculated. It happens to be a user
with passwords, so we also generate the password hash.


On Sun, May 24, 2015 at 7:48 PM, Matthieu Patou <mat at> wrote:
> Hello Matthias & Nadya,
> I was doing some profiling on some ldb actions.
> I was using source4/scripting/devel/addlotscontacts to generate lots of
> contacts and in the mean time I used perf.
> While analyzing the flame graph (attached) I realized that on 100% (on my
> machine) of my CPU time 18% was for doing the descriptor_add and 6% for
> password_hash_add.
> It means that password_hash_add is accouting for 30% of descriptor_add which
> in turn is a big CPU consumer.
> Is there a good reason why we go through this function ? Is it because it's
> bellow in the module stack ?
> Matthieu
> --
> Matthieu Patou
> Samba Team

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