Re: [patch 2.6.12-rc1-mm4] fork_connector: add a fork connector

Andrew Morton
2005-04-11T07:02:54Z

Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
>
> On Sun, Apr 10, 2005 at 10:43:24PM -0700, Jay Lan (jlan@engr.sgi.com) wrote:
> > I based my listen program on the fclisten.c posted by Kaigai Kohei
> > with my own modification. Unfortunately i lost my test machine in the
> > lab. I will recreate the listen program Monday. The original listener
> > did not validate sequence number. It also prints length of data and
> > sequence number of every message it receives. My listener prints
> > only out-of-sequence error messages.
> >
> > The fork generator fork-test.c was yours? I called it fork-test
> > and let it run continuously in while-loop:
> >
> > # while 1
> > # ./fork-test 10000000
> > # sleep 1
> > # end
> >
> > I let it do 10,000,000 times of fork continuously while the system
> > is running AIM7 and/or ubench.
> >
> > The original fclisten.c and fork-test.c are attached for your reference.
>
> It is pretty normal to see duplicated numbers in a fork test -
> I observed it too, since counter is incremented without locks
> we can catch situation when it is incremented simultaneously
> on both processors, the latest version of the fork connector
> from Guillaume contains processor id in the message and per cpu counters,
> so one can destinguish messages which sequence numbers will flow
> in a very similar way now.

Oh come on, that's just daft. Evgeniy, put a lock in there and fix it up.