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authorRusty Russell <rusty@rustcorp.com.au>2009-06-12 22:27:02 -0600
committerRusty Russell <rusty@rustcorp.com.au>2009-06-12 22:27:03 +0930
commita32a8813d0173163ba44d8f9556e0d89fdc4fb46 (patch)
treefddb6742338047d0219e8c2536cd39b04e643b16 /arch/x86/include
parentabd41f037e1a64543000ed73b42f616d04d92700 (diff)
downloadop-kernel-dev-a32a8813d0173163ba44d8f9556e0d89fdc4fb46.zip
op-kernel-dev-a32a8813d0173163ba44d8f9556e0d89fdc4fb46.tar.gz
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 'arch/x86/include')
-rw-r--r--arch/x86/include/asm/lguest_hcall.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/lguest_hcall.h b/arch/x86/include/asm/lguest_hcall.h
index faae199..f9a9f78 100644
--- a/arch/x86/include/asm/lguest_hcall.h
+++ b/arch/x86/include/asm/lguest_hcall.h
@@ -17,6 +17,7 @@
#define LHCALL_LOAD_TLS 16
#define LHCALL_NOTIFY 17
#define LHCALL_LOAD_GDT_ENTRY 18
+#define LHCALL_SEND_INTERRUPTS 19
#define LGUEST_TRAP_ENTRY 0x1F
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