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Re: [Qemu-devel] [PATCH COLO-Frame v10 17/38] COLO: synchronize PVM's st
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH COLO-Frame v10 17/38] COLO: synchronize PVM's state to SVM periodically |
Date: |
Fri, 13 Nov 2015 18:34:40 +0000 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
* zhanghailiang (address@hidden) wrote:
> Do checkpoint periodically, the default interval is 200ms.
>
> Signed-off-by: zhanghailiang <address@hidden>
> Signed-off-by: Li Zhijian <address@hidden>
> ---
> migration/colo.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/migration/colo.c b/migration/colo.c
> index 0efab21..a6791f4 100644
> --- a/migration/colo.c
> +++ b/migration/colo.c
> @@ -11,12 +11,19 @@
> */
>
> #include <unistd.h>
> +#include "qemu/timer.h"
> #include "sysemu/sysemu.h"
> #include "migration/colo.h"
> #include "trace.h"
> #include "qemu/error-report.h"
> #include "qemu/sockets.h"
>
> +/*
> + * checkpoint interval: unit ms
> + * Note: Please change this default value to 10000 when we support hybrid
> mode.
> + */
> +#define CHECKPOINT_MAX_PEROID 200
Why not put the patch that makes this a configurable parameter before this,
and then we can use it straight away?
> /* colo buffer */
> #define COLO_BUFFER_BASE_SIZE (4 * 1024 * 1024)
>
> @@ -183,6 +190,7 @@ out:
> static void colo_process_checkpoint(MigrationState *s)
> {
> QEMUSizedBuffer *buffer = NULL;
> + int64_t current_time, checkpoint_time =
> qemu_clock_get_ms(QEMU_CLOCK_HOST);
> int fd, ret = 0;
>
> /* Dup the fd of to_dst_file */
> @@ -220,11 +228,17 @@ static void colo_process_checkpoint(MigrationState *s)
> trace_colo_vm_state_change("stop", "run");
>
> while (s->state == MIGRATION_STATUS_COLO) {
> + current_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
> + if (current_time - checkpoint_time < CHECKPOINT_MAX_PEROID) {
> + g_usleep(100000);
> + continue;
> + }
I'm a bit concerned at the 100ms wait, when the period is 200ms;
depending how the times work out, couldn't we end up waiting for just
under 300ms? - that's a big error - and it's even more weird when
we make it configurable later.
I don't think we've got a sleep-until, which is a shame; but how
about something like:
if (current_time - checkpoint_time < CHECKPOINT_MAX_PEROID) {
int64_t delay_ms;
delay_ms = CHECKPOINT_MAX_PERIOD - (current_time - checkpoint_time);
g_usleep (delay_ms * 1000);
}
Dave
> /* start a colo checkpoint */
> ret = colo_do_checkpoint_transaction(s, buffer);
> if (ret < 0) {
> goto out;
> }
> + checkpoint_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
> }
>
> out:
> --
> 1.8.3.1
>
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
[Qemu-devel] [PATCH COLO-Frame v10 01/38] configure: Add parameter for configure to enable/disable COLO support, zhanghailiang, 2015/11/03
[Qemu-devel] [PATCH COLO-Frame v10 04/38] migration: Add state records for migration incoming, zhanghailiang, 2015/11/03
[Qemu-devel] [PATCH COLO-Frame v10 09/38] COLO: Implement colo checkpoint protocol, zhanghailiang, 2015/11/03