Before & After Under The Giant Lock

[binto]

Hi,

Thanks for all response, especially for Mr. Robert N M Watson
I read all , and i got a lot thing from conversation about this.

It's nice community, thanks once again.

Regards
Binto


> Roman Divacky wrote:
>> On Sun, Nov 25, 2007 at 02:41:35PM -0600, Stephen Montgomery-Smith
>> wrote:
>>>
>>> On Sun, 25 Nov 2007, Robert Watson wrote:
>>>
>>>> ........................
>>>> In FreeBSD 8, I expect we'll see a continued focus on both locking
>>>> granularity and improving opportunities for kernel parallelism by
>>>> better
>>>> distributing workloads over CPU pools.  This is important because the
>>>> number of cores/chip is continuing to increase dramatically, so MP
>>>> performance is going to be important to keep working on.  That said,
>>>> the
>>>> results to date have been extremely promising, and I anticipate that
>>>> we
>>>> will continue to find ways to better exploit multiprocessor hardware,
>>>> especially in the network stack.
>>>>
>>> I just want to add my 2 cents, that my recent experience with FreeBSD
>>> MP
>>> has been extremely positive.  I tend to use highly CPU bound MP
>>> programs,
>>> typically lots and lots of floating point operations.  It used to be
>>> that
>>> Linux beat FreeBSD hands down - now FreeBSD seems to have a slight
>>> edge!
>>> Basically my program runs about twice as fast when I run two threads as
>>> opposed to one - I cannot see doing any better than that!
>>
>> pure computation does not need kernel operations most of the time.. ie.
>> multi-threading kernel wont help much ;)
>
> It has an indirect benefit by (presumably) not being in contention
> with the userland process, and not needing slap Giant on the whole
> system every few milliseconds.
>
> Doug
>
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