Re: [Qemu-devel] [PATCH v13 12/13] Add set_cachesize command

[Blue Swirl]

On Wed, Jun 27, 2012 at 10:34 AM, Orit Wasserman <address@hidden> 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>
> ---
>  arch_init.c      |    9 +++++++++
>  hmp-commands.hx  |   18 ++++++++++++++++++
>  hmp.c            |   13 +++++++++++++
>  hmp.h            |    1 +
>  migration.c      |   23 ++++++++++++++++++++++-
>  migration.h      |    2 ++
>  qapi-schema.json |   16 ++++++++++++++++
>  qmp-commands.hx  |   23 +++++++++++++++++++++++
>  8 files changed, 104 insertions(+), 1 deletions(-)
>
> diff --git a/arch_init.c b/arch_init.c
> index bfc9f27..ae7c8b1 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -24,6 +24,7 @@
>  #include <stdint.h>
>  #include <stdarg.h>
>  #include <stdlib.h>
> +#include <math.h>
>  #ifndef _WIN32
>  #include <sys/types.h>
>  #include <sys/mman.h>
> @@ -192,6 +193,14 @@ static struct {
>     .cache = NULL,
>  };
>
> +
> +void xbzrle_cache_resize(int64_t new_size)
> +{
> +    if (XBZRLE.cache != NULL) {
> +        cache_resize(XBZRLE.cache, new_size/TARGET_PAGE_SIZE);

Please add spaces around '/'. Using checkpatch.pl would catch these.

> +    }
> +}
> +
>  static void save_block_hdr(QEMUFile *f, RAMBlock *block, ram_addr_t offset,
>         int cont, int flag)
>  {
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index a0c8df2..ef60dc0 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -829,6 +829,24 @@ STEXI
> address@hidden migrate_cancel
> address@hidden migrate_cancel
>  Cancel the current VM migration.
> +
> +ETEXI
> +
> +    {
> +        .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"
> +                     "The cache size effects the number of cache misses."
> +                     "In case of a high cache miss ratio you need to 
> increase the cache size",
> +        .mhandler.cmd = hmp_migrate_set_cachesize,
> +    },
> +
> +STEXI
> address@hidden migrate_set_cachesize @var{value}
> address@hidden migrate_set_cache
> +Set cache size to @var{value} (in bytes) for xbzrle migrations.
>  ETEXI
>
>     {
> diff --git a/hmp.c b/hmp.c
> index c275fab..0a27d2d 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -755,6 +755,19 @@ void hmp_migrate_set_downtime(Monitor *mon, const QDict 
> *qdict)
>     qmp_migrate_set_downtime(value, NULL);
>  }
>
> +void hmp_migrate_set_cachesize(Monitor *mon, const QDict *qdict)
> +{
> +    int64_t value = qdict_get_int(qdict, "value");
> +    Error *err = NULL;
> +
> +    qmp_migrate_set_cachesize(value, &err);
> +    if (err) {
> +        monitor_printf(mon, "%s\n", error_get_pretty(err));
> +        error_free(err);
> +        return;
> +    }
> +}
> +
>  void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict)
>  {
>     int64_t value = qdict_get_int(qdict, "value");
> diff --git a/hmp.h b/hmp.h
> index 09ba198..7c5117d 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -53,6 +53,7 @@ void hmp_migrate_cancel(Monitor *mon, const QDict *qdict);
>  void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict);
>  void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict);
>  void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict);
> +void hmp_migrate_set_cachesize(Monitor *mon, const QDict *qdict);
>  void hmp_set_password(Monitor *mon, const QDict *qdict);
>  void hmp_expire_password(Monitor *mon, const QDict *qdict);
>  void hmp_eject(Monitor *mon, const QDict *qdict);
> diff --git a/migration.c b/migration.c
> index 6063ed8..a892ae1 100644
> --- a/migration.c
> +++ b/migration.c
> @@ -22,6 +22,7 @@
>  #include "qemu_socket.h"
>  #include "block-migration.h"
>  #include "qmp-commands.h"
> +#include <math.h>
>
>  //#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 */
>  #define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024)
>
>  static NotifierList migration_state_notifiers =
> @@ -519,6 +520,26 @@ 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) {
> +        error_set(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
> +                  "exceeding address space");
> +        return;
> +    }
> +
> +    /* no change */
> +    if (value == s->xbzrle_cache_size) {
> +        return;
> +    }
> +
> +    s->xbzrle_cache_size = value;
> +    xbzrle_cache_resize(value);
> +}
> +
>  void qmp_migrate_set_speed(int64_t value, Error **errp)
>  {
>     MigrationState *s;
> diff --git a/migration.h b/migration.h
> index 4fe8122..83dba4a 100644
> --- a/migration.h
> +++ b/migration.h
> @@ -107,4 +107,6 @@ int xbzrle_decode_buffer(uint8_t *src, int slen, uint8_t 
> *dst, int dlen);
>  int migrate_use_xbzrle(void);
>  int64_t migrate_xbzrle_cache_size(void);
>
> +void xbzrle_cache_resize(int64_t new_size);
> +
>  #endif
> diff --git a/qapi-schema.json b/qapi-schema.json
> index ccc5eb3..982c93a 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -1379,6 +1379,22 @@
>  { 'command': 'migrate_set_speed', 'data': {'value': 'int'} }
>
>  ##
> +# @migrate_set_cachesize
> +#
> +# Set XBZRLE cache size
> +#
> +# @value: cache size in bytes
> +#
> +# The size will be round down to the nearest power of 2.
> +# The cache size can be modified before and during ongoing migration
> +#
> +# Returns: nothing on success
> +#
> +# Since: 1.2
> +##
> +{ 'command': 'migrate_set_cachesize', 'data': {'value': 'int'} }
> +
> +##
>  # @ObjectPropertyInfo:
>  #
>  # @name: the name of the property
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index 85b5920..0ca5cbb 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -520,6 +520,29 @@ Example:
>  <- { "return": {} }
>
>  EQMP
> +{
> +        .name       = "migrate_set_cachesize",
> +        .args_type  = "value:o",
> +        .mhandler.cmd_new = qmp_marshal_input_migrate_set_cachesize,
> +    },
> +
> +SQMP
> +migrate_set_cachesize
> +---------------------
> +
> +Set cache size to be used by XBZRLE migration, the cache size will be round 
> down
> +to the nearset power of 2
> +
> +Arguments:
> +
> +- "value": cache size in bytes (json-int)
> +
> +Example:
> +
> +-> { "execute": "migrate_set_cachesize", "arguments": { "value": 512M } }
> +<- { "return": {} }
> +
> +EQMP
>
>     {
>         .name       = "migrate_set_speed",
> --
> 1.7.7.6
>