cvs commit: src/sys/vm vm_contig.c vm_page.c vm_pageq.c vm_zeroidle.c

[Alan Cox]

Robert Watson wrote:

> On Mon, 5 Feb 2007, Alan Cox wrote:
>
>> alc         2007-02-05 06:02:55 UTC
>>
>>  FreeBSD src repository
>>
>>  Modified files:
>>    sys/vm               vm_contig.c vm_page.c vm_pageq.c
>>                         vm_zeroidle.c
>>  Log:
>>  Change the free page queue lock from a spin mutex to a default 
>> (blocking)
>>  mutex.  With the demise of Alpha support, there is no longer a 
>> reason for
>>  it to be a spin mutex.
>
>
> Is there any measurable performance change from this?  In the past, 
> I've observed significantly higher cost for acquiring spin mutexes vs. 
> sleep mutexes in micro-benchmarking.  The change was most striking on 
> Intel Xeon P4 hardware with an SMP kernel, and quite a bit less so on 
> other platforms.


I didn't notice any difference for buildworld on a 4-way Opteron.

Alan