On 2015.06.11 08:01 Prarit Bhargava wrote:
> On 06/11/2015 10:51 AM, Doug Smythies wrote:
>>
>> On 2015.06.10 16:46 Rafael J. Wysocki wrote:
>>> On Wednesday, June 10, 2015 09:18:45 AM Prarit Bhargava wrote:
>>>> I looked into switching to div64_s64() instead of the 32-bit version in
>>>> div_fp(), however, this would result in sample_ratio and core_busy
>>>> returning
>>>> 0 which is something we don't want.
>>
>> ???
>> Due to a great many overflow related issues, div_fp() was changed to
>> div64_s64()
>> a long time ago.
> Doug,
>
> Nope -- in a linux.git tree (up-to-date as of 7:00AM ET this AM)
>
> static inline int32_t div_fp(int32_t x, int32_t y)
> {
> return div_s64((int64_t)x << FRAC_BITS, y);
> }
> If we do want this to be div64_s64, I can make that change, however, I feel
> that
> a long delay like this should be ignored in the performance calculations in
> the
> driver and that's why I chose to go the direction I did.
Prarit,
Apologies to you and the list for the distraction. I mis-read "div_s64" as
"div64_s64".
Your suggestion is a good one.
I do maintain that my point about the duration method being flawed is valid.
I proposed a fix for that some time ago.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
