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| author | Rusty Russell <rusty@rustcorp.com.au> | 2009-06-13 06:27:02 +0200 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2009-06-12 14:57:03 +0200 |
| commit | a32a8813d0173163ba44d8f9556e0d89fdc4fb46 (patch) | |
| tree | fddb6742338047d0219e8c2536cd39b04e643b16 /drivers/lguest/lg.h | |
| parent | lguest: fix race in halt code (diff) | |
| download | linux-a32a8813d0173163ba44d8f9556e0d89fdc4fb46.tar.xz linux-a32a8813d0173163ba44d8f9556e0d89fdc4fb46.zip | |
lguest: improve interrupt handling, speed up stream networking
lguest never checked for pending interrupts when enabling interrupts, and
things still worked. However, it makes a significant difference to TCP
performance, so it's time we fixed it by introducing a pending_irq flag
and checking it on irq_restore and irq_enable.
These two routines are now too big to patch into the 8/10 bytes
patch space, so we drop that code.
Note: The high latency on interrupt delivery had a very curious
effect: once everything else was optimized, networking without GSO was
faster than networking with GSO, since more interrupts were sent and
hence a greater chance of one getting through to the Guest!
Note2: (Almost) Closing the same loophole for iret doesn't have any
measurable effect, so I'm leaving that patch for the moment.
Before:
1GB tcpblast Guest->Host: 30.7 seconds
1GB tcpblast Guest->Host (no GSO): 76.0 seconds
After:
1GB tcpblast Guest->Host: 6.8 seconds
1GB tcpblast Guest->Host (no GSO): 27.8 seconds
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/lguest/lg.h')
| -rw-r--r-- | drivers/lguest/lg.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h index 6743cf147d97..573896533ac9 100644 --- a/drivers/lguest/lg.h +++ b/drivers/lguest/lg.h @@ -139,8 +139,8 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user); #define pgd_pfn(x) (pgd_val(x) >> PAGE_SHIFT) /* interrupts_and_traps.c: */ -unsigned int interrupt_pending(struct lg_cpu *cpu); -void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq); +unsigned int interrupt_pending(struct lg_cpu *cpu, bool *more); +void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq, bool more); bool deliver_trap(struct lg_cpu *cpu, unsigned int num); void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i, u32 low, u32 hi); |