Virtualization - Dec 2015 - [PATCH v2] vhost: replace % with & on data path

On Mon, Nov 30, 2015 at 11:15:23AM +0200, Michael S. Tsirkin
wrote:
> We know vring num is a power of 2, so use &
> to mask the high bits.
> 
> Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
> ---
The generated code switches from DIV -> masking, source is clearer as well.

Tested-by: Venkatesh Srinivas <venkateshs at google.com>

-- vs;

On Fri, Dec 4, 2015 at 10:19 PM, Venkatesh Srinivas
<venkateshs at google.com> wrote:
> On Mon, Nov 30, 2015 at 11:15:23AM +0200, Michael S. Tsirkin wrote:
>> We know vring num is a power of 2, so use &
>> to mask the high bits.
>>
>> Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
>> ---
>
> The generated code switches from DIV -> masking, source is clearer as
well.
First impression was why, now it seems that compiler can't predict
this for variables.
For constants it would be optimized to the same, I suppose.
>
> Tested-by: Venkatesh Srinivas <venkateshs at google.com>
>
> -- vs;
> --
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-- 
With Best Regards,
Andy Shevchenko