Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 17 Nov 2008 22:22:16 +0300 | From | Cyrill Gorcunov <> | Subject | Re: [RFC] x86: save_args out of line |
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[Andi Kleen - Mon, Nov 17, 2008 at 07:23:40PM +0100] ... | | Ok. Hopefully it's worth the effort. The branch misprediction bubble | should not be too bad, perhaps it'll make up for the other cycles | you're adding. But even if it doesn't decreasing cache line foot print is | always a good thing. ...
May I turn in? :)
Original .macro interrupt func has
testl $3, CS(%rdi) je 1f SWAPGS 1: incl %gs:pda_irqcount jne 2f pop %rax mov %gs:pda_irqstackptr,%rsp push %rax 2: TRACE_IRQS_OFF
Wouldn't we help the branch predictor a bit by
testl $3, CS(%rdi) je 1f SWAPGS jne 2f 1: pop %rax mov %gs:pda_irqstackptr,%rsp push %rax 2: incl %gs:pda_irqcount TRACE_IRQS_OFF
I hope I didn't miss anything but maybe it's just a churning or plain wrong. Don't shoot me :)
- Cyrill -
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