On 08/23/2011 02:10 PM, Borislav Petkov wrote:
> On Tue, Aug 23, 2011 at 05:06:03PM -0400, H. Peter Anvin wrote:
>> On 08/23/2011 01:56 PM, Borislav Petkov wrote:
>>>
>>> But no, I don't think the difference has disappeared - to the contrary,
>>> AFAICT, the intention is for SYSCALL to be the fastest way to do
>>> syscalls on x86 due to diminished number of segment checks etc. INT80
>>> is legacy, slower, etc. I believe Andy measured a similar situation on
>>> Sandy Bridge with SYSCALL having latencies in the tens of nsecs range
>>> and INT80 being much slower. Ingo also measured a similar situation
>>> where the latency gap between the two on Intel is even bigger.
>>>
>>
>> Sandy Bridge doesn't have SYSCALL32 at all. It has SYSENTER and SYSCALL64.
>
> Yeah, I was talking about SYSCALL in general.
>
By the way, Borislav;
any way you could nudge your hardware people into
a) supporting SYSENTER in compatibility mode, and
b) giving us a way to turn SYSCALL *off* in compat mode?
... for future chips?
-hpa
------------------------------------------------------------------------------
EMC VNX: the world's simplest storage, starting under $10K
The only unified storage solution that offers unified management
Up to 160% more powerful than alternatives and 25% more efficient.
Guaranteed. http://p.sf.net/sfu/emc-vnx-dev2dev
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
