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Re: [PATCH v1] migration/dirtyrate: make sample page count configurable
From: |
David Edmondson |
Subject: |
Re: [PATCH v1] migration/dirtyrate: make sample page count configurable |
Date: |
Tue, 20 Apr 2021 15:09:52 +0100 |
On Thursday, 2021-04-15 at 01:23:54 +08, huangy wrote:
> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
>
> introduce optional sample-pages argument in calc-dirty-rate,
> making sample page count per GB configurable so that more
> accurate dirtyrate can be calculated.
>
> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
> ---
> migration/dirtyrate.c | 32 ++++++++++++++++++++++++++++----
> migration/dirtyrate.h | 8 +++++++-
> qapi/migration.json | 13 ++++++++++---
> 3 files changed, 45 insertions(+), 8 deletions(-)
>
> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> index ccb9814..43a531c 100644
> --- a/migration/dirtyrate.c
> +++ b/migration/dirtyrate.c
> @@ -48,6 +48,16 @@ static bool is_sample_period_valid(int64_t sec)
> return true;
> }
>
> +static bool is_sample_pages_valid(int64_t pages)
> +{
> + if (pages < MIN_SAMPLE_PAGE_COUNT ||
> + pages > MAX_SAMPLE_PAGE_COUNT) {
> + return false;
> + }
> +
> + return true;
> +}
Could be:
return pages >= MIN_SAMPLE_PAGE_COUNT &&
pages <= MAX_SAMPLE_PAGE_COUNT;
?
> +
> static int dirtyrate_set_state(int *state, int old_state, int new_state)
> {
> assert(new_state < DIRTY_RATE_STATUS__MAX);
> @@ -72,13 +82,15 @@ static struct DirtyRateInfo *query_dirty_rate_info(void)
> info->status = CalculatingState;
> info->start_time = DirtyStat.start_time;
> info->calc_time = DirtyStat.calc_time;
> + info->sample_pages = DirtyStat.sample_pages;
>
> trace_query_dirty_rate_info(DirtyRateStatus_str(CalculatingState));
>
> return info;
> }
>
> -static void init_dirtyrate_stat(int64_t start_time, int64_t calc_time)
> +static void init_dirtyrate_stat(int64_t start_time, int64_t calc_time,
> + uint64_t sample_pages)
> {
> DirtyStat.total_dirty_samples = 0;
> DirtyStat.total_sample_count = 0;
> @@ -86,6 +98,7 @@ static void init_dirtyrate_stat(int64_t start_time, int64_t
> calc_time)
> DirtyStat.dirty_rate = -1;
> DirtyStat.start_time = start_time;
> DirtyStat.calc_time = calc_time;
> + DirtyStat.sample_pages = sample_pages;
> }
>
> static void update_dirtyrate_stat(struct RamblockDirtyInfo *info)
> @@ -361,6 +374,7 @@ void *get_dirtyrate_thread(void *arg)
> int ret;
> int64_t start_time;
> int64_t calc_time;
> + uint64_t sample_pages;
>
> ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_UNSTARTED,
> DIRTY_RATE_STATUS_MEASURING);
> @@ -371,7 +385,8 @@ void *get_dirtyrate_thread(void *arg)
>
> start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
> calc_time = config.sample_period_seconds;
> - init_dirtyrate_stat(start_time, calc_time);
> + sample_pages = config.sample_pages_per_gigabytes;
> + init_dirtyrate_stat(start_time, calc_time, sample_pages);
>
> calculate_dirtyrate(config);
>
> @@ -383,7 +398,8 @@ void *get_dirtyrate_thread(void *arg)
> return NULL;
> }
>
> -void qmp_calc_dirty_rate(int64_t calc_time, Error **errp)
> +void qmp_calc_dirty_rate(int64_t calc_time, bool has_sample_pages,
> + int64_t sample_pages, Error **errp)
> {
> static struct DirtyRateConfig config;
> QemuThread thread;
> @@ -404,6 +420,13 @@ void qmp_calc_dirty_rate(int64_t calc_time, Error **errp)
> return;
> }
>
> + if (has_sample_pages && !is_sample_pages_valid(sample_pages)) {
> + error_setg(errp, "sample-pages is out of range[%d, %d].",
> + MIN_SAMPLE_PAGE_COUNT,
> + MAX_SAMPLE_PAGE_COUNT);
> + return;
> + }
Could set "sample_pages = DIRTYRATE_DEFAULT_SAMPLE_PAGES" in the else
clause, removing the need for...
> +
> /*
> * Init calculation state as unstarted.
> */
> @@ -415,7 +438,8 @@ void qmp_calc_dirty_rate(int64_t calc_time, Error **errp)
> }
>
> config.sample_period_seconds = calc_time;
> - config.sample_pages_per_gigabytes = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
> + config.sample_pages_per_gigabytes =
> + has_sample_pages ? sample_pages : DIRTYRATE_DEFAULT_SAMPLE_PAGES;
...checking again here.
> qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread,
> (void *)&config, QEMU_THREAD_DETACHED);
> }
> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
> index 6ec4295..5f987e2 100644
> --- a/migration/dirtyrate.h
> +++ b/migration/dirtyrate.h
> @@ -15,7 +15,6 @@
>
> /*
> * Sample 512 pages per GB as default.
> - * TODO: Make it configurable.
> */
> #define DIRTYRATE_DEFAULT_SAMPLE_PAGES 512
>
> @@ -35,6 +34,12 @@
> #define MIN_FETCH_DIRTYRATE_TIME_SEC 1
> #define MAX_FETCH_DIRTYRATE_TIME_SEC 60
>
> +/*
> + * Take 128 as minimum for sample dirty pages
> + */
This comment doesn't add any value - is there a reason for these values?
> +#define MIN_SAMPLE_PAGE_COUNT 128
> +#define MAX_SAMPLE_PAGE_COUNT 4096
> +
> struct DirtyRateConfig {
> uint64_t sample_pages_per_gigabytes; /* sample pages per GB */
> int64_t sample_period_seconds; /* time duration between two sampling */
> @@ -63,6 +68,7 @@ struct DirtyRateStat {
> int64_t dirty_rate; /* dirty rate in MB/s */
> int64_t start_time; /* calculation start time in units of second */
> int64_t calc_time; /* time duration of two sampling in units of second */
> + uint64_t sample_pages; /* sample pages per GB */
> };
>
> void *get_dirtyrate_thread(void *arg);
> diff --git a/qapi/migration.json b/qapi/migration.json
> index 9bf0bc4..868a867 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -1741,6 +1741,9 @@
> #
> # @calc-time: time in units of second for sample dirty pages
> #
> +# @sample-pages: page count per GB for sample dirty pages
> +# the default value is 512
> +#
> # Since: 5.2
> #
> ##
> @@ -1748,7 +1751,8 @@
> 'data': {'*dirty-rate': 'int64',
> 'status': 'DirtyRateStatus',
> 'start-time': 'int64',
> - 'calc-time': 'int64'} }
> + 'calc-time': 'int64',
> + 'sample-pages': 'uint64'} }
>
> ##
> # @calc-dirty-rate:
> @@ -1757,13 +1761,16 @@
> #
> # @calc-time: time in units of second for sample dirty pages
> #
> +# @sample-pages: page count per GB for sample dirty pages
> +# the default value is 512
> +#
> # Since: 5.2
> #
> # Example:
> -# {"command": "calc-dirty-rate", "data": {"calc-time": 1} }
> +# {"command": "calc-dirty-rate", "data": {"calc-time": 1, 'sample-pages':
> 512} }
> #
> ##
> -{ 'command': 'calc-dirty-rate', 'data': {'calc-time': 'int64'} }
> +{ 'command': 'calc-dirty-rate', 'data': {'calc-time': 'int64',
> '*sample-pages': 'int'} }
>
> ##
> # @query-dirty-rate:
> --
> 1.8.3.1
dme.
--
Don't you know you're never going to get to France.