On 2020/8/27 16:01, Zheng Chuan wrote:
>
>
> On 2020/8/26 18:17, David Edmondson wrote:
>> On Monday, 2020-08-24 at 17:14:37 +08, Chuan Zheng wrote:
>>
>>> Implement get_sample_page_period() and set_sample_page_period() to
>>> sleep specific time between sample actions.
>>>
>>> Signed-off-by: Chuan Zheng <zhengch...@huawei.com>
>>> ---
>>> migration/dirtyrate.c | 24 ++++++++++++++++++++++++
>>> migration/dirtyrate.h | 2 ++
>>> 2 files changed, 26 insertions(+)
>>>
>>> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
>>> index bd398b7..d1c0a78 100644
>>> --- a/migration/dirtyrate.c
>>> +++ b/migration/dirtyrate.c
>>> @@ -28,6 +28,30 @@
>>> static int CalculatingState = DIRTY_RATE_STATUS_UNSTARTED;
>>> static struct DirtyRateStat DirtyStat;
>>>
>>> +static int64_t set_sample_page_period(int64_t msec, int64_t initial_time)
>>> +{
>>> + int64_t current_time;
>>> +
>>> + current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
>>> + if ((current_time - initial_time) >= msec) {
>>> + msec = current_time - initial_time;
>>> + } else {
>>> + g_usleep((msec + initial_time - current_time) * 1000);
>>> + }
>>> +
>>> + return msec;
>>> +}
>>> +
>>> +static int64_t get_sample_page_period(int64_t sec)
>>> +{
>>> + if (sec <= MIN_FETCH_DIRTYRATE_TIME_SEC ||
>>
>> Shouldn't the minimum value be allowed?
>>
>> That is, this test should be "sec < MIN_FETCH_DIRTYRATE_TIME_SEC" and
>> MIN_FETCH_DIRTYRATE_TIME_SEC should be 1.
>>
> Well, Actually we could measure dirtyrate within duration below 1s, like 0.5s.
> Howerver, I am reconsider that maybe taking 0.5s as
> MIN_FETCH_DIRTYRATE_TIME_SEC is better in case of someone to do nasty thing
> like setting
> a meaningless time duration which is close to 0:)
>
Ouch, since i define sec as int64_t，it could never be 0.5s:-).
I will take 1s as minimum value because it will take about 100ms for large vm
to hash its result.
Thanks for your review.
>>> + sec > MAX_FETCH_DIRTYRATE_TIME_SEC) {
>>> + sec = DEFAULT_FETCH_DIRTYRATE_TIME_SEC;
>>> + }
>>> +
>>> + return sec;
>>> +}
>>> +
>>> static int dirtyrate_set_state(int *state, int old_state, int new_state)
>>> {
>>> assert(new_state < DIRTY_RATE_STATUS__MAX);
>>> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
>>> index 41bc264..50a5636 100644
>>> --- a/migration/dirtyrate.h
>>> +++ b/migration/dirtyrate.h
>>> @@ -51,6 +51,8 @@
>>>
>>> /* Take 1s as default for calculation duration */
>>> #define DEFAULT_FETCH_DIRTYRATE_TIME_SEC 1
>>> +#define MIN_FETCH_DIRTYRATE_TIME_SEC 0
>>> +#define MAX_FETCH_DIRTYRATE_TIME_SEC 60
>>>
>>> struct DirtyRateConfig {
>>> uint64_t sample_pages_per_gigabytes; /* sample pages per GB */
>>> --
>>> 1.8.3.1
>>
>> dme.
>>
