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authorRusty Russell <rusty@rustcorp.com.au>2009-06-12 22:27:03 -0600
committerRusty Russell <rusty@rustcorp.com.au>2009-06-12 22:27:03 +0930
commit61f4bc83fea248a3092beb7ba43daa5629615513 (patch)
tree5ce12fc0676f93a49f743dab1c60f8e1ca991ec3 /arch/x86/kernel/asm-offsets_32.c
parenta32a8813d0173163ba44d8f9556e0d89fdc4fb46 (diff)
downloadlinux-61f4bc83fea248a3092beb7ba43daa5629615513.tar.gz
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 <rusty@rustcorp.com.au>
Diffstat (limited to 'arch/x86/kernel/asm-offsets_32.c')
-rw-r--r--arch/x86/kernel/asm-offsets_32.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c
index 1a830cbd7015..dfdbf6403895 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();