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Re: [Qemu-devel] [PATCH v12 12/13] Add set_cachesize command
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH v12 12/13] Add set_cachesize command |
Date: |
Tue, 19 Jun 2012 13:13:26 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120605 Thunderbird/13.0 |
On 06/19/2012 09:43 AM, Orit Wasserman wrote:
> Change XBZRLE cache size in bytes (the size should be a power of 2).
> If XBZRLE cache size is too small there will be many cache miss.
>
> Signed-off-by: Benoit Hudzia <address@hidden>
> Signed-off-by: Petter Svard <address@hidden>
> Signed-off-by: Aidan Shribman <address@hidden>
> Signed-off-by: Orit Wasserman <address@hidden>
> ---
> +++ b/arch_init.c
> @@ -24,6 +24,7 @@
> #include <stdint.h>
> #include <stdarg.h>
> #include <stdlib.h>
> +#include <math.h>
What for?
> +
> + {
> + .name = "migrate_set_cachesize",
> + .args_type = "value:o",
> + .params = "value",
> + .help = "set cache size (in bytes) for XBZRLE migrations,"
> + "the cache size will be round down to the nearest power
> of 2.\n"
s/round/rounded/
> + "The cache size effects the number of cache misses."
s/effects/affects/
> +++ b/migration.c
> @@ -22,6 +22,7 @@
> #include "qemu_socket.h"
> #include "block-migration.h"
> #include "qmp-commands.h"
> +#include <math.h>
What for?
>
> //#define DEBUG_MIGRATION
>
> @@ -43,7 +44,7 @@ enum {
>
> #define MAX_THROTTLE (32 << 20) /* Migration speed throttling */
>
> -/* Migration XBZRLE cache size */
> +/* Migration XBZRLE default cache size */
Squash this change into the earlier patch that introduced the #define.
> #define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024)
>
> static NotifierList migration_state_notifiers =
> @@ -498,6 +499,26 @@ void qmp_migrate_cancel(Error **errp)
> migrate_fd_cancel(migrate_get_current());
> }
>
> +void qmp_migrate_set_cachesize(int64_t value, Error **errp)
> +{
> + MigrationState *s = migrate_get_current();
> +
> + /* Check for truncation */
> + if (value != (size_t)value) {
This fails to filter out a value of -1, at least on platforms where
size_t and int64_t are the same size. It might be better to use
explicit comparison:
if (value < 0 || value > SIZE_MAX)
> ##
> +# @migrate_set_cachesize
migrate-set-cachesize - QMP prefers '-' over '_'
> +#
> +# Set XBZRLE cache size
> +#
> +# @value: cache size in bytes
> +#
> +# The size will be round down to the nearest power of 2.
s/round/rounded/
> +
> +Set cache size to be used by XBZRLE migration, the cache size will be round
> down
s/round/rounded/
> +to the nearset power of 2
s/nearset/nearest/
> +
> +Arguments:
> +
> +- "value": cache size in bytes (json-int)
> +
> +Example:
> +
> +-> { "execute": "migrate_set_cachesize", "arguments": { "value": 512M } }
512M is not a valid json-int. Spell it out as 536870912.
--
Eric Blake address@hidden +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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- Re: [Qemu-devel] [PATCH v12 05/13] Add uleb encoding/decoding functions, (continued)
- [Qemu-devel] [PATCH v12 04/13] Add cache handling functions, Orit Wasserman, 2012/06/19
- [Qemu-devel] [PATCH v12 06/13] Add save_block_hdr function, Orit Wasserman, 2012/06/19
- [Qemu-devel] [PATCH v12 07/13] Add debugging infrastructure, Orit Wasserman, 2012/06/19
- [Qemu-devel] [PATCH v12 11/13] Add XBZRLE to ram_save_block and ram_save_live, Orit Wasserman, 2012/06/19
- [Qemu-devel] [PATCH v12 13/13] Add XBZRLE statistics, Orit Wasserman, 2012/06/19
- [Qemu-devel] [PATCH v12 12/13] Add set_cachesize command, Orit Wasserman, 2012/06/19
- Re: [Qemu-devel] [PATCH v12 12/13] Add set_cachesize command,
Eric Blake <=
- [Qemu-devel] [PATCH v12 09/13] Add migration_end function, Orit Wasserman, 2012/06/19
- [Qemu-devel] [PATCH v12 08/13] Change ram_save_block to return -1 if there are no more changes, Orit Wasserman, 2012/06/19
- [Qemu-devel] [PATCH v12 10/13] Add xbzrle_encode_buffer and xbzrle_decode_buffer functions, Orit Wasserman, 2012/06/19