Re: [PATCH] complib/cl_timer.c: fixing cl_timer calculation

[Yevgeny Kliteynik <kliteyn-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 24-Aug-10 2:55 PM, Yevgeny Kliteynik wrote:
> On 23-Aug-10 9:55 PM, Sasha Khapyorsky wrote:
>> On 17:38 Mon 23 Aug     , Yevgeny Kliteynik wrote:
>>> When calculating p_timer->timeout.tv_sec and p_timer->timeout.tv_nsec,
>>> the carry was ignored, resulting in wrong value in p_timer->timeout.tv_sec,
>>> and value>   10^9 in p_timer->timeout.tv_nsec (illegal value).
>>
>> Nice catch. And I also see a similar issue in cl_timer_trim().

BTW, any idea what are the (obviously historical)
reasons for these lines in the code?

323:	/* do not do 0 wait ! */
324:	/* if (delta_time < 1000.0) {delta_time = 1000;} */

-- Yevgeny

>> See a comments about the patch below.
>>
>>>
>>> Signed-off-by:  Yevgeny Kliteynik<kliteyn-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
>>>
>>> ---
>>>    opensm/complib/cl_timer.c |    8 +++++---
>>>    1 files changed, 5 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/opensm/complib/cl_timer.c b/opensm/complib/cl_timer.c
>>> index 2acdb51..09a5584 100644
>>> --- a/opensm/complib/cl_timer.c
>>> +++ b/opensm/complib/cl_timer.c
>>> @@ -299,7 +299,8 @@ cl_status_t cl_timer_start(IN cl_timer_t * const p_timer,
>>>    {
>>>    	struct timeval curtime;
>>>    	cl_list_item_t *p_list_item;
>>> -	uint32_t delta_time = time_ms;
>>> +	uint32_t delta_time_sec = time_ms / 1000;
>>> +	uint32_t delta_time_usec = (time_ms % 1000) * 1000;
>>
>> In order to prevent compatibility and porting issues would it be better
>> to use struct timeval's types here:
>>
>> 	time_t delta_time_sec;
>> 	suseconds_t delta_time_usec_t delta_time_usec;
>>
>> , instead of fixed size integers?
>>
>>>
>>>    	CL_ASSERT(p_timer);
>>>    	CL_ASSERT(p_timer->state == CL_INITIALIZED);
>>> @@ -324,9 +325,10 @@ cl_status_t cl_timer_start(IN cl_timer_t * const p_timer,
>>>    	/* if (delta_time<   1000.0) {delta_time = 1000;} */
>>>
>>>    	/* Calculate the timeout. */
>>> -	p_timer->timeout.tv_sec = curtime.tv_sec + (delta_time / 1000);
>>> +	p_timer->timeout.tv_sec = curtime.tv_sec + delta_time_sec +
>>> +		((curtime.tv_usec + delta_time_usec) / 1000000);
>>>    	p_timer->timeout.tv_nsec =
>>> -	    (curtime.tv_usec + ((delta_time % 1000) * 1000)) * 1000;
>>> +	    ((curtime.tv_usec + delta_time_usec) % 1000000) * 1000;
>>
>> Or even something like this:
>>
>> 	strcut timeval curtime, deltatime;
>>
>> 	gettimeofday(&curtime, NULL);
>>
>> 	addtime.tv_sec = time_ms / 1000;
>> 	addtime.tv_usec = (time_ms % 1000) * 1000;
>>
>> 	timeradd(&curtime,&addtime,&timer->timeout);
>>
>> ?
> 
> Sure, why not. It won't be that clean, because p_timer->timeout
> and curtime/deltatime are different types, but I get the idea.
> 
> -- Yevgeny
> 
>> Sasha
>>
>>>
>>>    	/* Add the timer to the queue. */
>>>    	if (cl_is_qlist_empty(&gp_timer_prov->queue)) {
>>> -- 
>>> 1.6.2.4
>>>
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>>
> 
> 

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