Re: [Qemu-devel] [PATCH 10/11] Add XBZRLE statistics

[Orit Wasserman]

On 07/31/2012 04:16 PM, Luiz Capitulino wrote:
> On Tue, 31 Jul 2012 11:31:09 +0300
> Orit Wasserman <address@hidden> wrote:
> 
>> On 07/30/2012 10:37 PM, Luiz Capitulino wrote:
>>> On Sun, 29 Jul 2012 12:43:02 +0300
>>> Orit Wasserman <address@hidden> wrote:
>>>
>>>> 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>
>>>> Signed-off-by: Juan Quintela <address@hidden>
>>>> ---
>>>>  arch_init.c      |   28 ++++++++++++++++++++++++++++
>>>>  hmp.c            |   21 +++++++++++++++++++++
>>>>  migration.c      |   28 ++++++++++++++++++++++++++++
>>>>  migration.h      |    4 ++++
>>>>  qapi-schema.json |   32 +++++++++++++++++++++++++++++++-
>>>>  qmp-commands.hx  |   35 +++++++++++++++++++++++++++++++++++
>>>>  6 files changed, 147 insertions(+), 1 deletions(-)
>>>>
>>>> diff --git a/arch_init.c b/arch_init.c
>>>> index 7f12317..9833d54 100644
>>>> --- a/arch_init.c
>>>> +++ b/arch_init.c
>>>> @@ -203,7 +203,11 @@ int64_t xbzrle_cache_resize(int64_t new_size)
>>>>  typedef struct AccountingInfo {
>>>>      uint64_t dup_pages;
>>>>      uint64_t norm_pages;
>>>> +    uint64_t xbzrle_bytes;
>>>> +    uint64_t xbzrle_pages;
>>>> +    uint64_t xbzrle_cache_miss;
>>>>      uint64_t iterations;
>>>> +    uint64_t xbzrle_overflows;
>>>>  } AccountingInfo;
>>>>  
>>>>  static AccountingInfo acct_info;
>>>> @@ -233,6 +237,26 @@ uint64_t norm_mig_pages_transferred(void)
>>>>      return acct_info.norm_pages;
>>>>  }
>>>>  
>>>> +uint64_t xbzrle_mig_bytes_transferred(void)
>>>> +{
>>>> +    return acct_info.xbzrle_bytes;
>>>> +}
>>>> +
>>>> +uint64_t xbzrle_mig_pages_transferred(void)
>>>> +{
>>>> +    return acct_info.xbzrle_pages;
>>>> +}
>>>> +
>>>> +uint64_t xbzrle_mig_pages_cache_miss(void)
>>>> +{
>>>> +    return acct_info.xbzrle_cache_miss;
>>>> +}
>>>> +
>>>> +uint64_t xbzrle_mig_pages_overflow(void)
>>>> +{
>>>> +    return acct_info.xbzrle_overflows;
>>>> +}
>>>> +
>>>>  static void save_block_hdr(QEMUFile *f, RAMBlock *block, ram_addr_t 
>>>> offset,
>>>>          int cont, int flag)
>>>>  {
>>>> @@ -257,6 +281,7 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t 
>>>> *current_data,
>>>>      if (!cache_is_cached(XBZRLE.cache, current_addr)) {
>>>>          cache_insert(XBZRLE.cache, current_addr,
>>>>                       g_memdup(current_data, TARGET_PAGE_SIZE));
>>>> +        acct_info.xbzrle_cache_miss++;
>>>>          return -1;
>>>>      }
>>>>  
>>>> @@ -274,6 +299,7 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t 
>>>> *current_data,
>>>>          return 0;
>>>>      } else if (encoded_len == -1) {
>>>>          DPRINTF("Overflow\n");
>>>> +        acct_info.xbzrle_overflows++;
>>>>          /* update data in the cache */
>>>>          memcpy(prev_cached_page, current_data, TARGET_PAGE_SIZE);
>>>>          return -1;
>>>> @@ -288,6 +314,8 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t 
>>>> *current_data,
>>>>      qemu_put_be16(f, encoded_len);
>>>>      qemu_put_buffer(f, XBZRLE.encoded_buf, encoded_len);
>>>>      bytes_sent = encoded_len + 1 + 2;
>>>> +    acct_info.xbzrle_pages++;
>>>> +    acct_info.xbzrle_bytes += bytes_sent;
>>>>  
>>>>      return bytes_sent;
>>>>  }
>>>> diff --git a/hmp.c b/hmp.c
>>>> index 9770d7b..383d5b1 100644
>>>> --- a/hmp.c
>>>> +++ b/hmp.c
>>>> @@ -172,6 +172,27 @@ void hmp_info_migrate(Monitor *mon)
>>>>                         info->disk->total >> 10);
>>>>      }
>>>>  
>>>> +    if (info->has_xbzrle_cache) {
>>>> +        monitor_printf(mon, "cache size: %" PRIu64 " bytes\n",
>>>> +                       info->xbzrle_cache->cache_size);
>>>> +        if (info->xbzrle_cache->has_xbzrle_bytes) {
>>>> +            monitor_printf(mon, "xbzrle transferred: %" PRIu64 " 
>>>> kbytes\n",
>>>> +                           info->xbzrle_cache->xbzrle_bytes >> 10);
>>>> +        }
>>>> +        if (info->xbzrle_cache->has_xbzrle_pages) {
>>>> +            monitor_printf(mon, "xbzrle pages: %" PRIu64 " pages\n",
>>>> +                           info->xbzrle_cache->xbzrle_pages);
>>>> +        }
>>>> +        if (info->xbzrle_cache->has_xbzrle_cache_miss) {
>>>> +            monitor_printf(mon, "xbzrle cache miss: %" PRIu64 "\n",
>>>> +                           info->xbzrle_cache->xbzrle_cache_miss);
>>>> +        }
>>>> +        if (info->xbzrle_cache->has_xbzrle_overflow) {
>>>> +            monitor_printf(mon, "xbzrle overflow : %" PRIu64 "\n",
>>>> +                           info->xbzrle_cache->xbzrle_overflow);
>>>> +        }
>>>> +    }
>>>> +
>>>>      qapi_free_MigrationInfo(info);
>>>>      qapi_free_MigrationParameters(params);
>>>>  }
>>>> diff --git a/migration.c b/migration.c
>>>> index 4dc99ba..fb802bc 100644
>>>> --- a/migration.c
>>>> +++ b/migration.c
>>>> @@ -136,6 +136,23 @@ MigrationParameters 
>>>> *qmp_query_migrate_parameters(Error **errp)
>>>>      return params;
>>>>  }
>>>>  
>>>> +static void get_xbzrle_cache_stats(MigrationInfo *info)
>>>> +{
>>>> +    if (migrate_use_xbzrle()) {
>>>> +        info->has_xbzrle_cache = true;
>>>> +        info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache));
>>>> +        info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size();
>>>> +        info->xbzrle_cache->has_xbzrle_bytes = true;
>>>> +        info->xbzrle_cache->xbzrle_bytes = xbzrle_mig_bytes_transferred();
>>>> +        info->xbzrle_cache->has_xbzrle_pages = true;
>>>> +        info->xbzrle_cache->xbzrle_pages = xbzrle_mig_pages_transferred();
>>>> +        info->xbzrle_cache->has_xbzrle_cache_miss = true;
>>>> +        info->xbzrle_cache->xbzrle_cache_miss = 
>>>> xbzrle_mig_pages_cache_miss();
>>>> +        info->xbzrle_cache->has_xbzrle_overflow = true;
>>>> +        info->xbzrle_cache->xbzrle_overflow = xbzrle_mig_pages_overflow();
>>>> +    }
>>>> +}
>>>> +
>>>>  MigrationInfo *qmp_query_migrate(Error **errp)
>>>>  {
>>>>      MigrationInfo *info = g_malloc0(sizeof(*info));
>>>> @@ -144,6 +161,13 @@ MigrationInfo *qmp_query_migrate(Error **errp)
>>>>      switch (s->state) {
>>>>      case MIG_STATE_SETUP:
>>>>          /* no migration has happened ever */
>>>> +
>>>> +        /* display xbzrle cache size */
>>>> +        if (migrate_use_xbzrle()) {
>>>> +            info->has_xbzrle_cache = true;
>>>> +            info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache));
>>>> +            info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size();
>>>> +        }
>>>
>>> Is it really useful to return this in MIG_SETUP? Can't the cache size
>>> be queried by some query- command?
>> I like it this way and it is very simple to use, you need to use 
>> query-migrate command if you do migration 
>> anyway.
> 
> But this will only be returned before a migration takes place. Then it will
> never be returned again. Doesn't seem to be the right place for it.
It is returned also in MIG_ACTIVE and MIG_COMPLETE (when XBZRLE are active).
> 
>> Otherwise we will need to add a query command for each configurable 
>> parameters,
>> so one for speed and another for downtime and probably more in the future.
> 
> I don't think this is a problem. We're trying to design QMP commands as we
> would design a C API, and I'd have different functions to query different 
> things.
> 
> Besides, let's not mix what's best to a human user and what's best for a
> machine protocol. If we add different query commands for different parameters,
> then it's possible to call them from 'info migrate' if you wish.
sounds reasonable, I will change it.

Orit 
> 
>> This way we use one command to query the migration setup.
> 
> Again, that information would only be returned before a first migration
> occurs.
> 
>>
>> Orit
>>>
>>>>          break;
>>>>      case MIG_STATE_ACTIVE:
>>>>          info->has_status = true;
>>>> @@ -166,8 +190,12 @@ MigrationInfo *qmp_query_migrate(Error **errp)
>>>>              info->disk->remaining = blk_mig_bytes_remaining();
>>>>              info->disk->total = blk_mig_bytes_total();
>>>>          }
>>>> +
>>>> +        get_xbzrle_cache_stats(info);
>>>>          break;
>>>>      case MIG_STATE_COMPLETED:
>>>> +        get_xbzrle_cache_stats(info);
>>>> +
>>>>          info->has_status = true;
>>>>          info->status = g_strdup("completed");
>>>>  
>>>> diff --git a/migration.h b/migration.h
>>>> index e4a7cd7..a9852fc 100644
>>>> --- a/migration.h
>>>> +++ b/migration.h
>>>> @@ -91,6 +91,10 @@ uint64_t dup_mig_bytes_transferred(void);
>>>>  uint64_t dup_mig_pages_transferred(void);
>>>>  uint64_t norm_mig_bytes_transferred(void);
>>>>  uint64_t norm_mig_pages_transferred(void);
>>>> +uint64_t xbzrle_mig_bytes_transferred(void);
>>>> +uint64_t xbzrle_mig_pages_transferred(void);
>>>> +uint64_t xbzrle_mig_pages_overflow(void);
>>>> +uint64_t xbzrle_mig_pages_cache_miss(void);
>>>>  
>>>>  /**
>>>>   * @migrate_add_blocker - prevent migration from proceeding
>>>> diff --git a/qapi-schema.json b/qapi-schema.json
>>>> index a936714..91dee72 100644
>>>> --- a/qapi-schema.json
>>>> +++ b/qapi-schema.json
>>>> @@ -275,6 +275,31 @@
>>>>             'total_time': 'int', 'duplicate': 'int', 'normal': 'int' } }
>>>>  
>>>>  ##
>>>> +# @XBZRLECacheStats
>>>> +#
>>>> +# Detailed XBZRLE migration cache statistics
>>>> +#
>>>> +# @cache-size: XBZRLE cache size
>>>> +#
>>>> +# @xbzrle-bytes: @optional, amount of bytes already transferred to the 
>>>> target VM
>>>> +#                only returned when migration is active or completed
>>>
>>> s/xbzrle-bytes/transferred-bytes
>>>
>>>> +#
>>>> +# @xbzrle-pages: @optional, amount of pages transferred to the target VM
>>>> +#                only returned when migration is active or completed
>>>
>>> s/xbzrle-pages/transferred-pages
>>>
>>>> +#
>>>> +# @xbzrle-cache-miss: @optional, number of cache miss
>>>> +#                     only returned when migration is active or completed
>>>
>>> s/xbzrle/xbzrle//
>>>
>>>> +#
>>>> +# @xbzrle-overflow: @optional, number of overflows
>>>> +#                   only returned when migration is active or completed
>>>
>>> s/xbzrle///
>>>
>>> Besides, all these parameters shouldn't be optional as they are 
>>> unconditionally
>>> included (BZRLECacheStats itself is optional as returned by query-migrate).
>>>
>>>> +#
>>>> +# Since: 1.2
>>>> +##
>>>> +{ 'type': 'XBZRLECacheStats',
>>>> +  'data': {'cache-size': 'int', '*xbzrle-bytes': 'int', '*xbzrle-pages': 
>>>> 'int',
>>>> +           '*xbzrle-cache-miss': 'int', '*xbzrle-overflow': 'int' } }
>>>> +
>>>> +##
>>>>  # @MigrationInfo
>>>>  #
>>>>  # Information about current migration process.
>>>> @@ -292,11 +317,16 @@
>>>>  #        status, only returned if status is 'active' and it is a block
>>>>  #        migration
>>>>  #
>>>> +# @xbzrle-cache: #optional @XBZRLECacheStats containing detailed XBZRLE
>>>> +#                migration statistics, only returned if XBZRLE feature is 
>>>> on
>>>> +#                (since 1.2)
>>>> +#
>>>>  # Since: 0.14.0
>>>>  ##
>>>>  { 'type': 'MigrationInfo',
>>>>    'data': {'*status': 'str', '*ram': 'MigrationStats',
>>>> -           '*disk': 'MigrationStats'} }
>>>> +           '*disk': 'MigrationStats',
>>>> +           '*xbzrle-cache': 'XBZRLECacheStats'} }
>>>>  
>>>>  ##
>>>>  # @query-migrate
>>>> diff --git a/qmp-commands.hx b/qmp-commands.hx
>>>> index a5a67eb..0546f42 100644
>>>> --- a/qmp-commands.hx
>>>> +++ b/qmp-commands.hx
>>>> @@ -2106,6 +2106,17 @@ The main json-object contains the following:
>>>>           - "transferred": amount transferred (json-int)
>>>>           - "remaining": amount remaining (json-int)
>>>>           - "total": total (json-int)
>>>> +- "xbzrle-cache": only present if XBZRLE is active.
>>>> +  It is a json-object with the following XBZRLE information:
>>>> +         - "cache-size": XBZRLE cache size
>>>> +         - "xbzrle-bytes": total XBZRLE bytes transferred, only present if
>>>> +                           status is "active" or "completed"
>>>> +         - "xbzrle-pages": number of XBZRLE compressed pages, only 
>>>> present if
>>>> +                           status is "active" or "completed"
>>>> +         - "cache-miss": number of cache misses, only present if
>>>> +                           status is "active" or "completed"
>>>> +         - "overflow": number of XBZRLE overflows, only present if
>>>> +                           status is "active" or "completed"
>>>>  Examples:
>>>>  
>>>>  1. Before the first migration
>>>> @@ -2170,6 +2181,30 @@ Examples:
>>>>        }
>>>>     }
>>>>  
>>>> +6. Migration is being performed and XBZRLE is active:
>>>> +
>>>> +-> { "execute": "query-migrate" }
>>>> +<- {
>>>> +      "return":{
>>>> +         "status":"active",
>>>> +         "capabilities" : [ { "capability": "xbzrle", "state" : true } ],
>>>> +         "ram":{
>>>> +            "total":1057024,
>>>> +            "remaining":1053304,
>>>> +            "transferred":3720,
>>>> +            "duplicate": 10,
>>>> +            "normal" : 3333
>>>> +         },
>>>> +         "cache":{
>>>> +            "cache-size": 1024
>>>> +            "xbzrle-transferred":20971520,
>>>> +            "xbzrle-pages":2444343,
>>>> +            "xbzrle-cache-miss":2244,
>>>> +            "xbzrle-overflow":34434
>>>> +         }
>>>> +      }
>>>> +   }
>>>> +
>>>>  EQMP
>>>>  
>>>>      {
>>>
>>
>