Improving the kernel/i386 timecounter performance (GSoC proposal)

[Scott Long]

David Xu wrote:
> Julian Elischer wrote:
>> David Xu wrote:
>>> David Xu wrote:
>>>> Julian Elischer wrote:
>>>>
>>>>> depends on the hardware.
>>>>> anyhow I was only saying it was possible, not necessarily
>>>>> good or even useful.
>>>>>
>>>>>
>>>>
>>>> I had done some works for thread private page shared by kernel
>>>> and userland when I was doing userland spinlock, if userland asks
>>>> a page, kernel will allocate it and put some interesting thing in
>>>> it by scheduler etcs, these code may be useful.
>>>>
>>> FYI:
>>> http://people.freebsd.org/~davidxu/schedctl/
>>
>> reading this quickly, you allocate a separately addressed page for
>> each thread, but,  how do you use it?
>>
>>
> I store the address in userland TLS area, then get it when I want to
> check some scheduling informations.
> 

Interesting, I was wondering earlier today if pointing to the per-thread
syspage in from the TLS area would save the TLB invalidate that you were
concerned about.

Scott