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

[Orit Wasserman]

On 06/27/2012 08:56 PM, Blue Swirl wrote:
> 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.
It actually does not catch it ...
> 
>> +    }
>> +}
>> +
>>  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
>>  @item migrate_cancel
>>  @findex 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
>>