Joe Kuan wrote:
> Just being curious. Why u suggest condvar over taskq_suspend/resume?
> Is there any pros/cons?
taskq_suspend won't do what you need it to do. It waits until the
current task has finished, and then doesn't start another one until
taskq_resume is done. If you taskq_dispatch for each little job (packet
or group of packets) then it would work, but if you're trying to get job
notification cheaply, a condvar will work simpler and faster.
-- Garrett
>
> 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
>>>>>>> opensolaris-code@opensolaris.org
>>>>>>> http://mail.opensolaris.org/mailman/listinfo/opensolaris-code
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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