[PATCH 2/4 - rev2] Add new timeval_to_sec function

[PATCH 2/4 - rev2] Add new timeval_to_sec function

[Varun Chandramohan]

A new function for converting timeval to time_t is added in time.h. Its a common function used in different
places.

Signed-off-by: Varun Chandramohan <varunc@linux.vnet.ibm.com>
---
 include/linux/time.h |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/include/linux/time.h b/include/linux/time.h
index 6a5f503..1faf65c 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -149,6 +149,18 @@ static inline s64 timeval_to_ns(const st
 }
 
 /**
+ * timeval_to_sec - Convert timeval to seconds
+ * @tv:         pointer to the timeval variable to be converted
+ *
+ * Returns the seconds representation of timeval parameter.
+ * Note : Here we round up the value. We dont need accuracy.
+ */
+static inline time_t timeval_to_sec(const struct timeval *tv)
+{
+	return (tv->tv_sec + (tv->tv_usec ? 1 : 0));
+}
+
+/**
  * ns_to_timespec - Convert nanoseconds to timespec
  * @nsec:	the nanoseconds value to be converted
  *
-- 
1.4.3.4

Re: [PATCH 2/4 - rev2] Add new timeval_to_sec function

[Stephen Hemminger]

On Mon, 20 Aug 2007 13:45:36 +0530
Varun Chandramohan <varunc@linux.vnet.ibm.com> wrote:

> A new function for converting timeval to time_t is added in time.h. Its a common function used in different
> places.
> 
> Signed-off-by: Varun Chandramohan <varunc@linux.vnet.ibm.com>
> ---
>  include/linux/time.h |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
> 
> diff --git a/include/linux/time.h b/include/linux/time.h
> index 6a5f503..1faf65c 100644
> --- a/include/linux/time.h
> +++ b/include/linux/time.h
> @@ -149,6 +149,18 @@ static inline s64 timeval_to_ns(const st
>  }
>  
>  /**
> + * timeval_to_sec - Convert timeval to seconds
> + * @tv:         pointer to the timeval variable to be converted
> + *
> + * Returns the seconds representation of timeval parameter.
> + * Note : Here we round up the value. We dont need accuracy.
> + */
> +static inline time_t timeval_to_sec(const struct timeval *tv)
> +{
> +	return (tv->tv_sec + (tv->tv_usec ? 1 : 0));
> +}
> +

Why roundup? Unless there is a requirement in the standard, please just
use the timeval seconds. In which case the inline is unneeded.


-- 
Stephen Hemminger <shemminger@linux-foundation.org>

Re: [PATCH 2/4 - rev2] Add new timeval_to_sec function

[Varun Chandramohan]

Stephen Hemminger wrote:
> On Mon, 20 Aug 2007 13:45:36 +0530
> Varun Chandramohan <varunc@linux.vnet.ibm.com> wrote:
>
>   
>> A new function for converting timeval to time_t is added in time.h. Its a common function used in different
>> places.
>>
>> Signed-off-by: Varun Chandramohan <varunc@linux.vnet.ibm.com>
>> ---
>>  include/linux/time.h |   12 ++++++++++++
>>  1 files changed, 12 insertions(+), 0 deletions(-)
>>
>> diff --git a/include/linux/time.h b/include/linux/time.h
>> index 6a5f503..1faf65c 100644
>> --- a/include/linux/time.h
>> +++ b/include/linux/time.h
>> @@ -149,6 +149,18 @@ static inline s64 timeval_to_ns(const st
>>  }
>>  
>>  /**
>> + * timeval_to_sec - Convert timeval to seconds
>> + * @tv:         pointer to the timeval variable to be converted
>> + *
>> + * Returns the seconds representation of timeval parameter.
>> + * Note : Here we round up the value. We dont need accuracy.
>> + */
>> +static inline time_t timeval_to_sec(const struct timeval *tv)
>> +{
>> +	return (tv->tv_sec + (tv->tv_usec ? 1 : 0));
>> +}
>> +
>>     
>
> Why roundup? Unless there is a requirement in the standard, please just
> use the timeval seconds. In which case the inline is unneeded.
>
>
>   
Thanks for the reply stephen. As you might be aware that this discussion
took place sometime ago when i posted my first patch set.
Initially it was like this:

return (tv->tv_sec + (tv->tv_usec + 500000)/1000000);
Then i got some comments from patrick and oliver. They wanted me to
round it up.

So what about rounding up with

return (tv->tv_sec + (tv->tv_usec + 999999)/1000000);


Then on second revision the above was changed to

return tv->tv_sec + (tv->tv_usec ? 1 : 0);

as it would be much faster. Since the timeval is meant for stats purpose
we decided not really bother about accuracy. My initial patch actually
took only sec value into account, but i was adviced to round up usec to
give a better o/p. Is that ok??? Or you still think we should consider
only secs?

Regards,
Varun

Re: [PATCH 2/4 - rev2] Add new timeval_to_sec function

[Bob Beers]

What if the name of the function was more descriptive of what the
 function actually does?  Maybe timeval_ceil_sec()?

Re: [PATCH 2/4 - rev2] Add new timeval_to_sec function

[Varun Chandramohan]

Bob Beers wrote:
> What if the name of the function was more descriptive of what the
>  function actually does?  Maybe timeval_ceil_sec()?
>   
Looks ok, it can be done if everyone is ok with it.
> -
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