[Click] Patch for nanosecond scheduling precision in ns-3-click

[Eddie Kohler]

Hi Sascha,

Both of these patches are for ns, so I can't apply them. Did you mean to 
send them elsewhere?

I just checked in a change that you should look at...

Eddie


On 2/11/12 3:18 PM, Sascha Alexander Jopen wrote:
> Hey,
>
> finally i've got some time to run simulations with the nanosecond
> precision changes. Well, they run with nanosecond precision.
>
> However, this does only work, when running the simulator with nanosecond
> or finer resolution. With lower resolution, the timestamp at which the
> event is scheduled is rounded down by the NS3 Time class. Because this
> depends on the resolution of NS3, this has to be fixed in
> HandleScheduleFromClick to the next matching timestamp. This is
> essentially the same as we did in click routerthread.cc to fix problems
> with nano-/microsecond precision. See the attached patch for a quick
> fix. This has to be applied to ns-3-dev as well, removing the
> microsecond part of it.
> Using other resolutions but the default resolution in ns3 has some
> disadvantages. Some models simply do not work with other resolutions,
> like the wifi dcf manager, which relies on us slottimes, for example.
>
> By the way, the last patch i submitted, which calls simclick_click_kill
> leads to segfaults when ns3 terminates with uninitialized click routers.
> The second patch fixes this (against ns-3-dev)
>
> Sascha
>
> On 01/25/12 21:41, Lalith Suresh wrote:
>> On Wed, Jan 25, 2012 at 9:40 PM, Eddie Kohler<ekohler at gmail.com>  wrote:
>>> Hi Lalith,
>>>
>>> This is fair enough. But we could add a sim-command that returned 0 if the
>>> current timestamp is a timespec. On Ns-2 this command would return -1. Then
>>> we could do what's appropriate within click.
>>>
>>
>> Alright. I'll have an update ready soon.
>>
>>> Eddie
>>>
>>>
>>>
>>> On 1/9/12 3:33 PM, Lalith Suresh wrote:
>>>>
>>>> Hi Eddy,
>>>>
>>>> On Mon, Jan 9, 2012 at 7:05 PM, Eddie Kohler<ekohler at gmail.com>   wrote:
>>>>>
>>>>> Hi Lalith,
>>>>>
>>>>> This change looks generally good, but surely ns defines some version
>>>>> variables that we can use to detect whether "cursimnode->curtime" is a
>>>>> timespec or a timeval. If it doesn't, then please add one: #define
>>>>> NS_CURTIME_IS_TIMESPEC 1. Then Click can be made to work cleanly with
>>>>> either, for instance:
>>>>>
>>>>> #if NS_CURTIME_IS_TIMESPEC
>>>>>   *ts = cursimnode->curtime;
>>>>> #else
>>>>>   ts->tv_sec = cursimnode->curtime.tv_sec;
>>>>>   ts->tv_nsec = cursimnode->curtime.tv_usec * 1000;
>>>>> #endif
>>>>>
>>>>> The timer scheduling code in routerthread.cc would also need a fork: #if
>>>>> CLICK_NS&&   NS_CURTIME_IS_TIMESPEC /timespec-code/ #elif CLICK_NS
>>>>> /timeval-code/ #endif.
>>>>>
>>>>> Make sense?
>>>>>
>>>>
>>>> Nopes (or I'm way too tired). :)
>>>>
>>>> I don't think a #define in ns-3 will help here. ns-3 links with
>>>> libnsclick.so dynamically, and "cursimnode->curtime" comes from
>>>> include/click/simclick.h (struct simclick_node). If we are to use the
>>>> preprocessor to fork the code appropriately, then we'd need to know
>>>> NS_CURTIME_IS_TIMESPEC during Click's compile time. Right?
>>>>
>>>>> Sascha, did you end up trying this?
>>>>> Eddie
>>>>>
>>>>>
>>>>>
>>>>> On 12/31/11 7:46 AM, Lalith Suresh wrote:
>>>>>>
>>>>>>
>>>>>> Hello all,
>>>>>>
>>>>>> After Sascha raised this issue on the ns-3-users list [1], I tried
>>>>>> making a quick patch to make Click's NS code use timespec, and make
>>>>>> the corresponding changes on the ns-3 side as well.
>>>>>>
>>>>>> I've pushed the changes to my ns-3-click [2] and Click [3]
>>>>>> repositories. Kindly review. I'll push to ns-3-dev once the Click side
>>>>>> changes are applied. Note that this will probably break the ns-2
>>>>>> patches for nsclick.
>>>>>>
>>>>>>
>>>>>> [1]
>>>>>>
>>>>>> http://groups.google.com/group/ns-3-users/browse_thread/thread/2be8d60531bd82a8
>>>>>> [2] http://code.nsnam.org/lalith/ns-3-click-dev
>>>>>> [3] https://github.com/lalithsuresh/click
>>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>>
>
>
>
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