Messages in this thread | | | Date | Sun, 28 Dec 2008 22:28:42 +0200 | From | Avi Kivity <> | Subject | Re: [PATCH 0/3] Remove interrupt stack table usage from x86_64 kernel |
| |
Andi Kleen wrote: >> This makes the whole thing unworthwhile. The vmload/vmsave pair costs >> only 200 cycles (I should have started with this), and 120 cycles on the >> heavyweight path plus complexity are not worth 200 cycles on the >> lightweight path. >> > > Actually to switch ISTs you need to change the TSS, not the IDT. > But I suppose that won't be any faster. >
I can't touch the TSS (that's the starting point of the exercise). The plan was to have a copy of the IDT with all IST pointers zeroed out (or to have per-cpu IDT and zero out the IST pointers when entering guest mode, restoring them on context switch).
It's not worth it though.
-- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.
| |