Matus UHLAR - fantomas wrote:

> On 05.11.08 12:09, Per Jessen wrote:
>> I have a very unusual situation (I think):
>>
>> I am running the exact same system (it was cloned) on several
>> single-core and dual-core systems. The only difference is in the
>> hardware, i.e. some systems are dual-core.

>
> cloned? Do you have the same OS kernel with support for more CPUs and
> CPUs with more cores on both machines?


Yes, it's the same SMP kernel on all machines.

>> I am running spamd with maxchild=25 (the actual number in use is
>> controlled externally).

>
> externally?


Sorry, I should have explained - the number of callers of spamd is being
controlled elsewhere.

>> The single-core systems vary from two to five, sometimes six.
>> Perfectly
>> normal. On the dual-core systems, I never see more than two active
>> children. Not normal.

>
> Why not normal? Maybe the dualcore CPU can handle all mail fast enough
> so there's no need for spawning more children


OK, I also know there is a queue building up on the dual-core systems,
but hardly any queueing on the single-core.

>> Notice that the single-core system reports "handled cleanup of child
>> pid nnnnn due to SIGCHLD" which is never seen on the dual-core
>> system, and that the dual-core reports "child nnnnn killed
>> successfully", which is
>> never seen on the single-core system. What am I missing here?

>
> While I am not sure what do those messages mean, I think that there
> should be no difference between handling of processes independently on
> number of CPUs/cores whatever. I guess that's problem of OS, not SA.


Quite probably, but the symptoms are showing in SA, not in the OS :-)
Also, in 3.1.7 this all worked just fine, although with a different
kernel version.


/Per Jessen, Z├╝rich