The patch titled
lguest: speed up PARAVIRT_LAZY_FLUSH handling
has been added to the -mm tree. Its filename is
lguest-speed-up-paravirt_lazy_flush-handling.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: lguest: speed up PARAVIRT_LAZY_FLUSH handling
From: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
When Zach Amsden added PARAVIRT_LAZY_FLUSH I didn't realize how often it would
get called. We only need to do something if we're actually in lazy mode.
Before:
Time for one context switch via pipe: 10509 (9863 - 18761)
Time for one Copy-on-Write fault: 71796 (20625 - 207750)
Time to exec client once: 1076218 (1066203 - 1085937)
Time for one fork/exit/wait: 1193125 (574750 - 1197750)
Time for two PTE updates: 10844 (10659 - 20703)
After:
Time for one context switch via pipe: 6745 (6521 - 13966)
Time for one Copy-on-Write fault: 44734 (11468 - 91988)
Time to exec client once: 815984 (801218 - 878218)
Time for one fork/exit/wait: 1023250 (397687 - 1030375)
Time for two PTE updates: 6699 (6475 - 9279)
(Native for comparison):
Time for one context switch via pipe: 4031 (3212 - 4146)
Time for one Copy-on-Write fault: 4402 (4388 - 4426)
Time to exec client once: 343859 (336859 - 349484)
Time for one fork/exit/wait: 120234 (118500 - 136140)
Time for two PTE updates: 2269 (2261 - 2272)
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/lguest/lguest.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)
diff -puN drivers/lguest/lguest.c~lguest-speed-up-paravirt_lazy_flush-handling drivers/lguest/lguest.c
--- a/drivers/lguest/lguest.c~lguest-speed-up-paravirt_lazy_flush-handling
+++ a/drivers/lguest/lguest.c
@@ -59,9 +59,10 @@ static __initdata const struct lguest_bo
static enum paravirt_lazy_mode lazy_mode;
static void lguest_lazy_mode(enum paravirt_lazy_mode mode)
{
- if (mode == PARAVIRT_LAZY_FLUSH)
- hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0);
- else {
+ if (mode == PARAVIRT_LAZY_FLUSH) {
+ if (unlikely(lazy_mode != PARAVIRT_LAZY_NONE))
+ hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0);
+ } else {
lazy_mode = mode;
if (mode == PARAVIRT_LAZY_NONE)
hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0);
_
Patches currently in -mm which might be from rusty@xxxxxxxxxxxxxxx are
mm-clean-up-and-kernelify-shrinker-registration.patch
use-menuconfig-objects-ii-module-menu.patch
fix-stop_machine_run-problem-with-naughty-real-time-process.patch
cpu-hotplug-fix-ksoftirqd-termination-on-cpu-hotplug-with-naughty-realtime-process.patch
cpu-hotplug-fix-ksoftirqd-termination-on-cpu-hotplug-with-naughty-realtime-process-fix.patch
define-new-percpu-interface-for-shared-data.patch
use-the-new-percpu-interface-for-shared-data.patch
lguest-export-symbols-for-lguest-as-a-module.patch
lguest-the-guest-code.patch
lguest-the-guest-code-tidyups.patch
lguest-the-guest-code-tidyups-update.patch
lguest-the-guest-code-update-for-mm-disable-tsc-dont-set-pge-bit.patch
lguest-speed-up-paravirt_lazy_flush-handling.patch
lguest-the-host-code.patch
lguest-the-host-code-tidyups.patch
lguest-the-host-code-tidyups-update.patch
lguest-the-host-code-borkages.patch
lguest-the-asm-offsets.patch
lguest-the-makefile-and-kconfig.patch
lguest-the-makefile-and-kconfig-tidyups.patch
lguest-the-console-driver.patch
lguest-the-console-driver-tidyups.patch
lguest-the-net-driver.patch
lguest-the-net-driver-tidyups.patch
lguest-the-net-driver-tidyups-update.patch
lguest-the-block-driver.patch
lguest-the-block-driver-tidyups.patch
lguest-the-block-driver-tidyups-update.patch
lguest-the-documentation-example-launcher.patch
lguest-more-lazy_hcalls.patch
lguest-faster-tls-switching.patch
mm-clean-up-and-kernelify-shrinker-registration-reiser4.patch
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