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[Qemu-devel] [PATCH] vl: Adjust the place of calling mlockall to speedup
From: |
zhanghailiang |
Subject: |
[Qemu-devel] [PATCH] vl: Adjust the place of calling mlockall to speedup VM's startup |
Date: |
Tue, 23 Sep 2014 15:57:47 +0800 |
If we configure mlock=on and memory policy=bind at the same time,
It will consume lots of time for system to treat with memory,
especially when call mbind after mlockall.
Adjust the place of calling mlockall, calling mbind before mlockall
can remarkably reduce the time of VM's startup.
Signed-off-by: zhanghailiang <address@hidden>
---
Hi,
Actually, for mbind and mlockall, i have made a test about the time consuming
for the different call sequence.
The results is shown below. It is obviously that mlockall called before mbind
is
more time-consuming.
Besides, this patch is OK with memory hotplug.
TEST CODE:
if (mbind_first) {
printf("mbind --> mlockall\n");
mbind(ptr, ram_size/2, MPOL_BIND, &node0mask, 2,
MPOL_MF_STRICT | MPOL_MF_MOVE);
mbind(ptr + ram_size/2, ram_size/2, MPOL_BIND, &node1mask, 2,
MPOL_MF_STRICT | MPOL_MF_MOVE);
mlockall(MCL_CURRENT | MCL_FUTURE);
} else {
printf("mlockall --> mbind\n");
mlockall(MCL_CURRENT | MCL_FUTURE);
mbind(ptr, ram_size/2, MPOL_BIND, &node0mask, 2 ,
MPOL_MF_STRICT | MPOL_MF_MOVE);
mbind(ptr + ram_size/2, ram_size/2, MPOL_BIND, &node1mask, 2,
MPOL_MF_STRICT | MPOL_MF_MOVE);
}
RESULT 1:
#time /home/test_mbind 10240 0
memroy size 10737418240
mlockall --> mbind
real 0m11.886s
user 0m0.004s
sys 0m11.865s
#time /home/test_mbind 10240 1
memroy size 10737418240
mbind --> mlockall
real 0m5.334s
user 0m0.000s
sys 0m5.324s
RESULT 2:
#time /home/test_mbind 4096 0
memroy size 4294967296
mlockall --> mbind
real 0m5.503s
user 0m0.000s
sys 0m5.492s
#time /home/test_mbind 4096 1
memroy size 4294967296
mbind --> mlockall
real 0m2.139s
user 0m0.000s
sys 0m2.132s
Best Regards,
zhanghailiang
---
vl.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/vl.c b/vl.c
index dc792fe..adf4770 100644
--- a/vl.c
+++ b/vl.c
@@ -134,6 +134,7 @@ const char* keyboard_layout = NULL;
ram_addr_t ram_size;
const char *mem_path = NULL;
int mem_prealloc = 0; /* force preallocation of physical target memory */
+int enable_mlock = false;
int nb_nics;
NICInfo nd_table[MAX_NICS];
int autostart;
@@ -1421,12 +1422,8 @@ static void smp_parse(QemuOpts *opts)
}
-static void configure_realtime(QemuOpts *opts)
+static void realtime_init(void)
{
- bool enable_mlock;
-
- enable_mlock = qemu_opt_get_bool(opts, "mlock", true);
-
if (enable_mlock) {
if (os_mlock() < 0) {
fprintf(stderr, "qemu: locking memory failed\n");
@@ -3973,7 +3970,7 @@ int main(int argc, char **argv, char **envp)
if (!opts) {
exit(1);
}
- configure_realtime(opts);
+ enable_mlock = qemu_opt_get_bool(opts, "mlock", true);
break;
case QEMU_OPTION_msg:
opts = qemu_opts_parse(qemu_find_opts("msg"), optarg, 0);
@@ -4441,6 +4438,8 @@ int main(int argc, char **argv, char **envp)
machine_class->init(current_machine);
+ realtime_init();
+
audio_init();
cpu_synchronize_all_post_init();
--
1.7.12.4
- [Qemu-devel] [PATCH] vl: Adjust the place of calling mlockall to speedup VM's startup,
zhanghailiang <=