Messages in this thread | | | Date | Thu, 23 Apr 2015 15:52:26 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86/asm/entry/32: Restore %ss before SYSRETL if necessary |
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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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