Re: Can context switches be faster?

Chase Venters
2006-10-13T14:51:55Z

On Fri, 13 Oct 2006, James Courtier-Dutton wrote:

> Arjan van de Ven wrote:
>> On Thu, 2006-10-12 at 14:25 -0400, John Richard Moser wrote:
>>
>>
>>> - Does the current code act on these behaviors, or just flush all
>>> cache regardless?
>>
>> the cache flushing is a per architecture property. On x86, the cache
>> flushing isn't needed; but a TLB flush is. Depending on your hardware
>> that can be expensive as well.
>>
>
> So, that is needed for a full process context switch to another process.
> Is the context switch between threads quicker as it should not need to
> flush the TLB?

Indeed. This is also true for switching from a process to a kernel thread
and back, because kernel threads don't have their own user-space virtual
memory; they just live inside the kernel virtual memory mapped into every
process.

> James
>

Thanks,
Chase