RE: Bogomips and loops_per_jiffy

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

[-- Attachment #1: Type: text/plain, Size: 1240 bytes --]

Hi Paul & Gabriel !

We indeed have some weird stuff mixing signed & unsigned in the
arch/ppc/kernel/time.c code. The patch enclosed, from Jean-Denis
Boyer, seems the right fix, except for one thing: I'd rather
change the test from >= to > (which in the old could would mean
changing the while (... < 0 to <= 0) as I see no reason to trigger
a new decrementer interrupt in ... 0 ticks !

Can you confirm it's ok to push ?

Regards,
Ben.

>
>Troy,
>with the patch, now, it completely hangs.
>The reason is that in timer_interrupt()
>
>	while ((next_dec = tb_ticks_per_jiffy - tb_delta(&jiffy_stamp)) < 0)
>{
>
>Now that next_dec is unsigned, this condition is always false.
>
>Here is another patch I suggest to replace yours.
>Its in attachement to this email.
>I tested it, and it seems OK.
>
>I did not include your modification made to the type of local variables in
>function do_settimeofday().
>I do not see how it is related to our problem.
>
>
>--------------------------------------------
> Jean-Denis Boyer, B.Eng., System Architect
> Mediatrix Telecom Inc.
> 4229 Garlock Street
> Sherbrooke (Québec)
> J1L 2C8  CANADA
> (819)829-8749 x241
>--------------------------------------------
>

[-- Attachment #2: patch.time.2 --]
[-- Type: application/binary, Size: 1076 bytes --]