Re: [PATCH] x86/asm/entry/32: Restore %ss before SYSRETL if necessary

[H. Peter Anvin]

On 04/23/2015 03:38 PM, Andy Lutomirski wrote:
>>
>> Because there are way more sysrets than context switches, and Linux is
>> particularly sensitive to system call latency, by design.
> 

Just to clarify: why would Linux be more sensitive to system call by
design?  It enables much simpler APIs and avoids hacks like sending down
a syscall task list (which was genuinely proposed at one point.)  If
kernel entry/exit is too expensive, then the APIs get more complex
because they *have* to do everything in the smallest number of system calls.

	-hpa


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