From 61f4bc83fea248a3092beb7ba43daa5629615513 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 12 Jun 2009 22:27:03 -0600 Subject: lguest: optimize by coding restore_flags and irq_enable in assembler. The downside of the last patch which made restore_flags and irq_enable check interrupts is that they are now too big to be patched directly into the callsites, so the C versions are always used. But the C versions go via PV_CALLEE_SAVE_REGS_THUNK which saves all the registers. In fact, we don't need any registers in the fast path, so we can do better than this if we actually code them in assembler. The results are in the noise, but since it's about the same amount of code, it's worth applying. 1GB Guest->Host: input(suppressed),output(suppressed) Before: Seconds: 0:16.53 Packets: 377268,753673 Interrupts: 22461,24297 Notifications: 1(5245),21303(732370) Net IRQs triggered: 377023(245),42578(711095) After: Seconds: 0:16.48 Packets: 377289,753673 Interrupts: 22281,24465 Notifications: 1(5245),21296(732377) Net IRQs triggered: 377060(229),42564(711109) Signed-off-by: Rusty Russell --- arch/x86/kernel/asm-offsets_32.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/x86/kernel/asm-offsets_32.c') diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c index 1a830cbd701..dfdbf640389 100644 --- a/arch/x86/kernel/asm-offsets_32.c +++ b/arch/x86/kernel/asm-offsets_32.c @@ -126,6 +126,7 @@ void foo(void) #if defined(CONFIG_LGUEST) || defined(CONFIG_LGUEST_GUEST) || defined(CONFIG_LGUEST_MODULE) BLANK(); OFFSET(LGUEST_DATA_irq_enabled, lguest_data, irq_enabled); + OFFSET(LGUEST_DATA_irq_pending, lguest_data, irq_pending); OFFSET(LGUEST_DATA_pgdir, lguest_data, pgdir); BLANK(); -- cgit v1.2.3