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Re: [Qemu-devel] [PATCH 05/12] migration: show the statistics of compres
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH 05/12] migration: show the statistics of compression |
Date: |
Wed, 13 Jun 2018 17:25:08 +0100 |
User-agent: |
Mutt/1.10.0 (2018-05-17) |
* address@hidden (address@hidden) wrote:
> From: Xiao Guangrong <address@hidden>
>
> Then the uses can adjust the parameters based on this info
>
> Currently, it includes:
> pages: amount of pages compressed and transferred to the target VM
> busy: amount of count that no free thread to compress data
> busy-rate: rate of thread busy
> reduced-size: amount of bytes reduced by compression
> compression-rate: rate of compressed size
>
> Signed-off-by: Xiao Guangrong <address@hidden>
> ---
> hmp.c | 13 +++++++++++++
> migration/migration.c | 11 +++++++++++
> migration/ram.c | 37 +++++++++++++++++++++++++++++++++++++
> migration/ram.h | 1 +
> qapi/migration.json | 25 ++++++++++++++++++++++++-
> 5 files changed, 86 insertions(+), 1 deletion(-)
>
> diff --git a/hmp.c b/hmp.c
> index ef93f4878b..5c2d3bd318 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -269,6 +269,19 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
> info->xbzrle_cache->overflow);
> }
>
> + if (info->has_compression) {
> + monitor_printf(mon, "compression pages: %" PRIu64 " pages\n",
> + info->compression->pages);
> + monitor_printf(mon, "compression busy: %" PRIu64 "\n",
> + info->compression->busy);
> + monitor_printf(mon, "compression busy rate: %0.2f\n",
> + info->compression->busy_rate);
> + monitor_printf(mon, "compression reduced size: %" PRIu64 "\n",
> + info->compression->reduced_size);
> + monitor_printf(mon, "compression rate: %0.2f\n",
> + info->compression->compression_rate);
> + }
> +
> if (info->has_cpu_throttle_percentage) {
> monitor_printf(mon, "cpu throttle percentage: %" PRIu64 "\n",
> info->cpu_throttle_percentage);
> diff --git a/migration/migration.c b/migration/migration.c
> index 05aec2c905..bf7c63a5a2 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -693,6 +693,17 @@ static void populate_ram_info(MigrationInfo *info,
> MigrationState *s)
> info->xbzrle_cache->overflow = xbzrle_counters.overflow;
> }
>
> + if (migrate_use_compression()) {
> + info->has_compression = true;
> + info->compression = g_malloc0(sizeof(*info->compression));
> + info->compression->pages = compression_counters.pages;
> + info->compression->busy = compression_counters.busy;
> + info->compression->busy_rate = compression_counters.busy_rate;
> + info->compression->reduced_size = compression_counters.reduced_size;
> + info->compression->compression_rate =
> + compression_counters.compression_rate;
> + }
> +
> if (cpu_throttle_active()) {
> info->has_cpu_throttle_percentage = true;
> info->cpu_throttle_percentage = cpu_throttle_get_percentage();
> diff --git a/migration/ram.c b/migration/ram.c
> index ee03b28435..80914b747e 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -292,6 +292,15 @@ struct RAMState {
> uint64_t num_dirty_pages_period;
> /* xbzrle misses since the beginning of the period */
> uint64_t xbzrle_cache_miss_prev;
> +
> + /* compression statistics since the beginning of the period */
> + /* amount of count that no free thread to compress data */
> + uint64_t compress_thread_busy_prev;
> + /* amount bytes reduced by compression */
> + uint64_t compress_reduced_size_prev;
> + /* amount of compressed pages */
> + uint64_t compress_pages_prev;
> +
> /* number of iterations at the beginning of period */
> uint64_t iterations_prev;
> /* Iterations since start */
> @@ -329,6 +338,8 @@ struct PageSearchStatus {
> };
> typedef struct PageSearchStatus PageSearchStatus;
>
> +CompressionStats compression_counters;
> +
> struct CompressParam {
> bool done;
> bool quit;
> @@ -1147,6 +1158,24 @@ static void migration_update_rates(RAMState *rs,
> int64_t end_time)
> rs->xbzrle_cache_miss_prev) / iter_count;
> rs->xbzrle_cache_miss_prev = xbzrle_counters.cache_miss;
> }
> +
> + if (migrate_use_compression()) {
> + uint64_t comp_pages;
> +
> + compression_counters.busy_rate = (double)(compression_counters.busy -
> + rs->compress_thread_busy_prev) / iter_count;
> + rs->compress_thread_busy_prev = compression_counters.busy;
> +
> + comp_pages = compression_counters.pages - rs->compress_pages_prev;
> + if (comp_pages) {
> + compression_counters.compression_rate =
> + (double)(compression_counters.reduced_size -
> + rs->compress_reduced_size_prev) /
> + (comp_pages * TARGET_PAGE_SIZE);
> + rs->compress_pages_prev = compression_counters.pages;
> + rs->compress_reduced_size_prev =
> compression_counters.reduced_size;
> + }
> + }
> }
>
> static void migration_bitmap_sync(RAMState *rs)
> @@ -1412,6 +1441,9 @@ static void flush_compressed_data(RAMState *rs)
> qemu_mutex_lock(&comp_param[idx].mutex);
> if (!comp_param[idx].quit) {
> len = qemu_put_qemu_file(rs->f, comp_param[idx].file);
> + /* 8 means a header with RAM_SAVE_FLAG_CONTINUE. */
> + compression_counters.reduced_size += TARGET_PAGE_SIZE - len + 8;
I think I'd rather save just len+8 rather than than the subtraction.
I think other than that, and Eric's comments, it's OK.
Dave
> + compression_counters.pages++;
> ram_counters.transferred += len;
> }
> qemu_mutex_unlock(&comp_param[idx].mutex);
> @@ -1441,6 +1473,10 @@ static int compress_page_with_multi_thread(RAMState
> *rs, RAMBlock *block,
> qemu_cond_signal(&comp_param[idx].cond);
> qemu_mutex_unlock(&comp_param[idx].mutex);
> pages = 1;
> + /* 8 means a header with RAM_SAVE_FLAG_CONTINUE. */
> + compression_counters.reduced_size += TARGET_PAGE_SIZE -
> + bytes_xmit + 8;
> + compression_counters.pages++;
> ram_counters.transferred += bytes_xmit;
> break;
> }
> @@ -1760,6 +1796,7 @@ static int ram_save_target_page(RAMState *rs,
> PageSearchStatus *pss,
> if (res > 0) {
> return res;
> }
> + compression_counters.busy++;
> }
>
> return ram_save_page(rs, pss, last_stage);
> diff --git a/migration/ram.h b/migration/ram.h
> index d386f4d641..7b009b23e5 100644
> --- a/migration/ram.h
> +++ b/migration/ram.h
> @@ -36,6 +36,7 @@
>
> extern MigrationStats ram_counters;
> extern XBZRLECacheStats xbzrle_counters;
> +extern CompressionStats compression_counters;
>
> int xbzrle_cache_resize(int64_t new_size, Error **errp);
> uint64_t ram_bytes_remaining(void);
> diff --git a/qapi/migration.json b/qapi/migration.json
> index 3ec418dabf..a11987cdc4 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -72,6 +72,26 @@
> 'cache-miss': 'int', 'cache-miss-rate': 'number',
> 'overflow': 'int' } }
>
> +##
> +# @CompressionStats:
> +#
> +# Detailed compression migration statistics
> +#
> +# @pages: amount of pages compressed and transferred to the target VM
> +#
> +# @busy: amount of count that no free thread to compress data
> +#
> +# @busy-rate: rate of thread busy
> +#
> +# @reduced-size: amount of bytes reduced by compression
> +#
> +# @compression-rate: rate of compressed size
> +#
> +##
> +{ 'struct': 'CompressionStats',
> + 'data': {'pages': 'int', 'busy': 'int', 'busy-rate': 'number',
> + 'reduced-size': 'int', 'compression-rate': 'number' } }
> +
> ##
> # @MigrationStatus:
> #
> @@ -169,6 +189,8 @@
> # only present when the postcopy-blocktime migration capability
> # is enabled. (Since 2.13)
> #
> +# @compression: compression migration statistics, only returned if
> compression
> +# feature is on and status is 'active' or 'completed' (Since 2.14)
> #
> # Since: 0.14.0
> ##
> @@ -183,7 +205,8 @@
> '*cpu-throttle-percentage': 'int',
> '*error-desc': 'str',
> '*postcopy-blocktime' : 'uint32',
> - '*postcopy-vcpu-blocktime': ['uint32']} }
> + '*postcopy-vcpu-blocktime': ['uint32'],
> + '*compression': 'CompressionStats'} }
>
> ##
> # @query-migrate:
> --
> 2.14.4
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [PATCH 03/12] migration: fix counting xbzrle cache_miss_rate, (continued)
[Qemu-devel] [PATCH 07/12] migration: hold the lock only if it is really needed, guangrong . xiao, 2018/06/04