Just being curious. Why u suggest condvar over taskq_suspend/resume?
Is there any pros/cons?
Thanks
Joe
On 15 Jul 2008, at 01:24, Garrett D'Amore wrote:
> Joe Kuan wrote:
>>
>> On 14 Jul 2008, at 23:50, Garrett D'Amore wrote:
>>
>>> Joe Kuan wrote:
>>>> Hi Garrett,
>>>>
>>>> Thank you for the quick response. The reason I need to kernelise
>>>> the network application as it needs to process 1.3/1.4 millions
>>>> packet
>>>> per second. Do you think using the taskqueue api has any impact
>>>> on the
>>>> performance? In FreeBSD, we are hitting around 80% cpu usage.
>>>
>>> If you want to create a single thread, you can do it with a taskq
>>> function that simply never routines. Its kind of ugly, but it will
>>> work. (It might prevent suspend/resume, though.)
>>
>> Sorry, can you give me more clue/detail on how to do that? What do
>> you
>> mean
>> by 'can do it with a taskq function that never routines'? Do u mean
>> taskq_create? However, I
>> still need to somehow attach my routine with the thread. Without
>> using
>> taskq_dispatch,
>> how else can I possibly do it?
>
> Just do taskq_dispatch *once*. The task function can run forever.
>
>>
>> To give you more information,
>> my function is simply consumes all the packets inside a queue (if
>> there is any) every millisecond.
>> This function is waken up every ms. In FreeBSD, there are tsleep()
>> and
>> wakeup(). I basically stuck
>> the wakup call inside some clock routine runs every ms.
>
> That actually sounds like a poor design, because it won't work with a
> tickless kernel, and it kills power savings measures done on some
> CPUs.
>
> You might want to think about possible alternatives, depending on the
> problem you are trying to solve.
>
> -- Garrett
>>
>> Many thanks
>> Joe
>>
>>>>
>>>> Also my function for the network applications takes a mbuf*
>>>> parameter and processes it. However, if I call ddi_taskq_dispatch
>>>> for
>>>> each incoming packet (mbuf), that will require quite a large pool.
>>>> Will the task pool get exhausted?
>>>
>>> You don't have to do that.
>>>>
>>>> Alternatively, should I make the function as an infinite loop
>>>> instead and pass on to taskq_dispatch only once, then relying on
>>>> taskq_resume/suspend when packet is ready. Would this be better?
>>>
>>> You shouldn't use taskq_suspend/resume. You don't need to do
>>> that. You
>>> could use your own condvars to signal that.
>>>
>>> Actually, you probably want to have a logic that allows for the
>>> function
>>> to run "while there is work to do", and then don't bother to use
>>> taskq_dispatch if the function can be shown to be "running". Then
>>> if
>>> function isn't already processing work, you can do taskq_dispatch().
>>>
>>> -- Garrett
>>>>
>>>> Many thanks
>>>> Joe
>>>>
>>>> On 14 Jul 2008, at 21:43, Garrett D'Amore wrote:
>>>>
>>>>> I'd try first to use a taskq -- ddi_taskq_create(9F) -- they are
>>>>> documented, and should be stable.
>>>>>
>>>>> -- Garrett
>>>>>
>>>>> Joe Kuan wrote:
>>>>>> Hi all,
>>>>>>
>>>>>> I have managed to kernelised our network application into
>>>>>> FreeBSD
>>>>>> and worked very well. Now, I start the same process on
>>>>>> OpenSolaris.
>>>>>> Although I have got the Solaris Internal book with me, it really
>>>>>> explains how everything works together. What I need is some
>>>>>> tutorial
>>>>>> or example on how to use kernel functions
>>>>>>
>>>>>> On FreeBSD, I can do something like
>>>>>>
>>>>>> SYSINIT(foo, ..);
>>>>>>
>>>>>> void foo(void *bar) {
>>>>>>
>>>>>> .....
>>>>>> kthread_create(my_func, ....);
>>>>>> }
>>>>>>
>>>>>>
>>>>>> void my_func(void *arg) {
>>>>>>
>>>>>> while (1) {
>>>>>>
>>>>>> do something
>>>>>>
>>>>>> sleep until timeout or wakeup by another signal
>>>>>> }
>>>>>> }
>>>>>>
>>>>>> where SYSINIT is to dispatch kernel thread at startup
>>>>>>
>>>>>> Here is the link of man page of kthread_create,
>>>>>> http://www.FreeBSD.org/cgi/man.cgi?query=kthread_create&apropos=0&sektion=0&manpath=FreeBSD+6.3-stable&format=html
>>>>>>
>>>>>>
>>>>>>
>>>>>> Here is the link of the info and showing how to use SYSINIT,
>>>>>> http://www.freebsd.org/doc/en_US.ISO8859-1/books/arch-handbook/sysinit.html
>>>>>>
>>>>>>
>>>>>>
>>>>>> I would be appreciate if anyone can point me to any document/
>>>>>> source
>>>>>> file/man pages/anything on the usage of creating a kernel thread
>>>>>> using
>>>>>> thread_create and also the equivalent mechanism of SYSINIT in
>>>>>> OpenSolaris.
>>>>>>
>>>>>> Many many thanks in advance.
>>>>>> Joe
>>>>>> _______________________________________________
>>>>>> opensolaris-code mailing list
>>>>>> [email protected]
>>>>>> http://mail.opensolaris.org/mailman/listinfo/opensolaris-code
>>>>>>
>>>>>
>>>>
>>>
>>
>
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