[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [RFC PATCH v4 23/28] COLO: Improve checkpoint efficienc
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [RFC PATCH v4 23/28] COLO: Improve checkpoint efficiency by do additional periodic checkpoint |
Date: |
Mon, 18 May 2015 17:48:59 +0100 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
* zhanghailiang (address@hidden) wrote:
> Besides normal checkpoint which according to the result of net packets
> comparing, We do additional checkpoint periodically, it will reduce the number
> of dirty pages when do one checkpoint, if we don't do checkpoint for a long
> time (This is a special case when the net packets is always consistent).
>
> Signed-off-by: zhanghailiang <address@hidden>
> Signed-off-by: Yang Hongyang <address@hidden>
> ---
> migration/colo.c | 29 +++++++++++++++++++++--------
> 1 file changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/migration/colo.c b/migration/colo.c
> index 9ef4554..da5bc5e 100644
> --- a/migration/colo.c
> +++ b/migration/colo.c
> @@ -10,6 +10,7 @@
> * later. See the COPYING file in the top-level directory.
> */
>
> +#include "qemu/timer.h"
> #include "sysemu/sysemu.h"
> #include "migration/migration-colo.h"
> #include "qemu/error-report.h"
> @@ -32,6 +33,13 @@
> */
> #define CHECKPOINT_MIN_PERIOD 100 /* unit: ms */
>
> +/*
> + * force checkpoint timer: unit ms
> + * this is large because COLO checkpoint will mostly depend on
> + * COLO compare module.
> + */
> +#define CHECKPOINT_MAX_PEROID 10000
> +
> enum {
> COLO_READY = 0x46,
>
> @@ -340,14 +348,7 @@ static void *colo_thread(void *opaque)
> proxy_checkpoint_req = colo_proxy_compare();
> if (proxy_checkpoint_req < 0) {
> goto out;
> - } else if (!proxy_checkpoint_req) {
> - /*
> - * No checkpoint is needed, wait for 1ms and then
> - * check if we need checkpoint again
> - */
> - g_usleep(1000);
> - continue;
> - } else {
> + } else if (proxy_checkpoint_req) {
> int64_t interval;
>
> current_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
> @@ -357,8 +358,20 @@ static void *colo_thread(void *opaque)
> g_usleep((1000*(CHECKPOINT_MIN_PERIOD - interval)));
> }
> DPRINTF("Net packets is not consistent!!!\n");
> + goto do_checkpoint;
> + }
> +
> + /*
> + * No proxy checkpoint is request, wait for 100ms
> + * and then check if we need checkpoint again.
> + */
> + current_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
> + if (current_time - checkpoint_time < CHECKPOINT_MAX_PEROID) {
> + g_usleep(100000);
> + continue;
This 100ms sleep is interesting - can you explain it's purpose; is it
just to save CPU time in the colo thread? It used to be 1ms (above
and in the previous version).
The MIN_PERIOD already stops the checkpoints being too close together,
so this is a separate sleep from that.
Dave
> }
>
> +do_checkpoint:
> /* start a colo checkpoint */
> if (colo_do_checkpoint_transaction(s, colo_control)) {
> goto out;
> --
> 1.7.12.4
>
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [RFC PATCH v4 23/28] COLO: Improve checkpoint efficiency by do additional periodic checkpoint,
Dr. David Alan Gilbert <=