Re: [PATCH v7 11/12] migration/dirtyrate: Implement qmp_cal_dirty_rate()/qmp_get_dirty_rate() function

[Zheng Chuan]

On 2020/9/10 22:27, Li Qiang wrote:
> Chuan Zheng <zhengchuan@huawei.com> 于2020年9月9日周三 下午10:14写道：
>>
>> Implement qmp_cal_dirty_rate()/qmp_get_dirty_rate() function which could be 
>> called
>>
>> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
>> ---
>>  migration/dirtyrate.c | 62 
>> +++++++++++++++++++++++++++++++++++++++++++++++++++
>>  qapi/migration.json   | 50 +++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 112 insertions(+)
>>
>> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
>> index 2f9ac34..e9e9e35 100644
>> --- a/migration/dirtyrate.c
>> +++ b/migration/dirtyrate.c
>> @@ -61,6 +61,24 @@ static int dirtyrate_set_state(int *state, int old_state, 
>> int new_state)
>>      }
>>  }
>>
>> +static struct DirtyRateInfo *query_dirty_rate_info(void)
>> +{
>> +    int64_t dirty_rate = DirtyStat.dirty_rate;
>> +    struct DirtyRateInfo *info = g_malloc0(sizeof(DirtyRateInfo));
>> +
>> +    if (CalculatingState == DIRTY_RATE_STATUS_MEASURED) {
> 
> Should we use atomic read 'CalculatingState'? The qmp thread maybe run
> with the sampled thread.
> 
OK, will optimize it in V8
>> +        info->dirty_rate = dirty_rate;
>> +    } else {
>> +        info->dirty_rate = -1;
>> +    }
>> +
>> +    info->status = CalculatingState;
>> +    info->start_time = DirtyStat.start_time;
>> +    info->calc_time = DirtyStat.calc_time;
>> +
>> +    return info;
>> +}
>> +
> 
> 
>>  static void reset_dirtyrate_stat(void)
>>  {
>>      DirtyStat.total_dirty_samples = 0;
>> @@ -331,6 +349,8 @@ static void calculate_dirtyrate(struct DirtyRateConfig 
>> config)
>>
>>      msec = config.sample_period_seconds * 1000;
>>      msec = set_sample_page_period(msec, initial_time);
>> +    DirtyStat.start_time = initial_time / 1000;
>> +    DirtyStat.calc_time = msec / 1000;
>>
>>      rcu_read_lock();
>>      if (compare_page_hash_info(block_dinfo, block_index) < 0) {
>> @@ -362,3 +382,45 @@ void *get_dirtyrate_thread(void *arg)
>>                                DIRTY_RATE_STATUS_MEASURED);
>>      return NULL;
>>  }
>> +
>> +void qmp_calc_dirty_rate(int64_t calc_time, Error **errp)
>> +{
>> +    static struct DirtyRateConfig config;
>> +    QemuThread thread;
>> +    int ret;
>> +
>> +    /*
>> +     * If the dirty rate is already being measured, don't attempt to start.
>> +     */
>> +    if (CalculatingState == DIRTY_RATE_STATUS_MEASURING) {
> 
> atomic read?
> 
>> +        error_setg(errp, "the dirty rate is already being measured.");
>> +        return;
>> +    }
>> +
>> +    if (!get_sample_page_period(calc_time)) {
>> +        error_setg(errp, "calc-time is out of range[%d, %d].",
>> +                         MIN_FETCH_DIRTYRATE_TIME_SEC,
>> +                         MAX_FETCH_DIRTYRATE_TIME_SEC);
>> +        return;
>> +    }
>> +
>> +    /*
>> +     * Init calculation state as unstarted.
>> +     */
>> +    ret = dirtyrate_set_state(&CalculatingState, CalculatingState,
>> +                              DIRTY_RATE_STATUS_UNSTARTED);
>> +    if (ret == -1) {
>> +        error_setg(errp, "init dirty rate calculation state failed.");
>> +        return;
>> +    }
>> +
>> +    config.sample_period_seconds = calc_time;
>> +    config.sample_pages_per_gigabytes = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
>> +    qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread,
>> +                       (void *)&config, QEMU_THREAD_DETACHED);
>> +}
>> +
>> +struct DirtyRateInfo *qmp_query_dirty_rate(Error **errp)
>> +{
>> +    return query_dirty_rate_info();
>> +}
>> diff --git a/qapi/migration.json b/qapi/migration.json
>> index 061ff25..4b980a0 100644
>> --- a/qapi/migration.json
>> +++ b/qapi/migration.json
>> @@ -1737,3 +1737,53 @@
>>  ##
>>  { 'enum': 'DirtyRateStatus',
>>    'data': [ 'unstarted', 'measuring', 'measured'] }
>> +
>> +##
>> +# @DirtyRateInfo:
>> +#
>> +# Information about current dirty page rate of vm.
>> +#
>> +# @dirty-rate: @dirtyrate describing the dirty page rate of vm
>> +#          in units of MB/s.
>> +#          If this field return '-1', it means querying is not
>> +#          start or not complete.
>> +#
>> +# @status: status containing dirtyrate query status includes
>> +#          'unstarted' or 'measuring' or 'measured'
>> +#
>> +# @start-time: start time in units of second for calculation
>> +#
>> +# @calc-time: time in units of second for sample dirty pages
>> +#
>> +# Since: 5.2
>> +#
>> +##
>> +{ 'struct': 'DirtyRateInfo',
>> +  'data': {'dirty-rate': 'int64',
>> +           'status': 'DirtyRateStatus',
>> +           'start-time': 'int64',
>> +           'calc-time': 'int64'} }
>> +
>> +##
>> +# @calc-dirty-rate:
>> +#
>> +# start calculating dirty page rate for vm
>> +#
>> +# @calc-time: time in units of second for sample dirty pages
>> +#
>> +# Since: 5.2
>> +#
>> +# Example:
>> +#   {"command": "calc-dirty-rate", "data": {"calc-time": 1} }
>> +#
>> +##
>> +{ 'command': 'calc-dirty-rate', 'data': {'calc-time': 'int64'} }
>> +
>> +##
>> +# @query-dirty-rate:
>> +#
>> +# query dirty page rate in units of MB/s for vm
>> +#
>> +# Since: 5.2
>> +##
>> +{ 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' }
>> --
>> 1.8.3.1
>>
>>
> 
> .
>