Re: [PATCH] fix do_xor_speed 64-bit devision issue on 32-bits arch

[Benny Halevy <bhalevy@tonian.com>]

No problem.  I'll revert it then.

Thanks,

Benny

On Sun, Dec 25, 2011 at 5:25 PM, Boaz Harrosh <bharrosh@panasas.com> wrote:
> On 12/25/2011 07:31 AM, Benny Halevy wrote:
>> On 2011-12-23 15:25, Jim Rees wrote:
>>> fanchaoting wrote:
>>>
>>>   Benny Halevy 写道:
>>>   > I am trying to build a pnfs client on a 32 bit system  and the
>>>   > pnfs-latest  kernel fails to compile. I get the following error
>>>   >
>>>   >  >  Building modules, stage 2.
>>>   >  >  TEST    posttest
>>>   >  > MODPOST 2046 modules
>>>   >  >ERROR: "__udivdi3" [crypto/xor.ko] undefined!
>>>   >  >make[1]: *** [__modpost] Error 1
>>>   >  >make: *** [modules] Error 2
>>>   >  >make: *** Waiting for unfinished jobs....
>>>   >  >Succeed: decoded and checked 1244492 instructions
>>>   >
>>>   > Reported-by: Rita Sequeira <rita.prajval@gmail.com>
>>>   > Signed-off-by: Benny Halevy <bhalevy@tonian.com>
>>>   > ---
>>>   >
>>>   > untested patch yet...
>>>   >
>>>   >  crypto/xor.c |    3 ++-
>>>   >  1 files changed, 2 insertions(+), 1 deletions(-)
>>>   >
>>>   > diff --git a/crypto/xor.c b/crypto/xor.c
>>>   > index 65433f5..2151ded 100644
>>>   > --- a/crypto/xor.c
>>>   > +++ b/crypto/xor.c
>>>   > @@ -95,7 +95,8 @@
>>>   >
>>>   >          ns_end -= ns_begin;
>>>   >          if (ns_end > 0)
>>>   > -                speed = BENCH_SIZE / 1024 * count * NSEC_PER_SEC / ns_end;
>>>   > +                speed = BENCH_SIZE / 1024 * count *
>>>   > +                                (unsigned)(NSEC_PER_SEC / ns_end);
>>>   >          else
>>>   >                  speed = 17;
>>>   >          tmpl->speed = speed;
>>>
>>>   Hi,I also meet this problem ,but when  i use you patch ,i can't solve this
>>>   problem.
>>>
>>> Maybe something like this?
>>>
>>> speed = do_div(BENCH_SIZE, 1024) * count * do_div(NSEC_PER_SEC, ns_end);
>>>
>>> This might not be exactly right because it changes the operator precedence,
>>> but it should eliminate the calls to __udivdi3.
>>
>> Hmm, you mean execution order? (which you do not)
>> C (and fortunately gcc too :) treats multiplication and division with the
>> same priority and executes them from left to right...
>>
>> Boaz, please ack...
>>
>
> Hi
>
> Please trash this patch for now. I will carry it out of tree for my use.
> (Looks I'm the only one who's using UML and the XOR engine)
>
> By next Connectathon I'll have a better patch sent to the right
> people.
>
> Thanks for your efforts, and sorry for the grief it caused.
> Boaz
>
>> Benny
>>
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