| Message ID | 1587352003-3312-3-git-send-email-wei.w.wang@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Migration xbzrle changes | expand |
On Mon, Apr 20, 2020 at 11:06:43AM +0800, Wei Wang wrote: > Users may need to check the xbzrle encoding rate to know if the guest > memory is xbzrle encoding-friendly, and dynamically turn off the > encoding if the encoding rate is low. > > Signed-off-by: Yi Sun <yi.y.sun@intel.com> > Signed-off-by: Wei Wang <wei.w.wang@intel.com> > --- > migration/migration.c | 1 + > migration/ram.c | 31 +++++++++++++++++++++++++++++-- > monitor/hmp-cmds.c | 2 ++ > qapi/migration.json | 5 ++++- > slirp | 2 +- > 5 files changed, 37 insertions(+), 4 deletions(-) > > diff --git a/migration/migration.c b/migration/migration.c > index 8e7ee0d76b..84a556a4ac 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -930,6 +930,7 @@ static void populate_ram_info(MigrationInfo *info, MigrationState *s) > info->xbzrle_cache->pages = xbzrle_counters.pages; > info->xbzrle_cache->cache_miss = xbzrle_counters.cache_miss; > info->xbzrle_cache->cache_miss_rate = xbzrle_counters.cache_miss_rate; > + info->xbzrle_cache->encoding_rate = xbzrle_counters.encoding_rate; > info->xbzrle_cache->overflow = xbzrle_counters.overflow; > } > > diff --git a/migration/ram.c b/migration/ram.c > index bca5878f25..c87c38ec80 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -327,6 +327,10 @@ struct RAMState { > uint64_t num_dirty_pages_period; > /* xbzrle misses since the beginning of the period */ > uint64_t xbzrle_cache_miss_prev; > + /* Amount of xbzrle pages since the beginning of the period */ > + uint64_t xbzrle_pages_prev; > + /* Amount of encoded bytes since the beginning of the period */ > + uint64_t encoded_size_prev; > > /* compression statistics since the beginning of the period */ > /* amount of count that no free thread to compress data */ > @@ -696,6 +700,18 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data, > return -1; > } > > + /* > + * Reaching here means the page has hit the xbzrle cache, no matter what > + * encoding result it is (normal encoding, overflow or skipping the page), > + * count the page as encoded. This is used to caculate the encoding rate. > + * > + * Example: 2 pages (8KB) being encoded, first page encoding generates 2KB, > + * 2nd page turns out to be skipped (i.e. no new bytes written to the > + * page), the overall encoding rate will be 8KB / 2KB = 4, which has the > + * skipped page included. In this way, the encoding rate can tell if the > + * guest page is good for xbzrle encoding. > + */ > + xbzrle_counters.pages++; > prev_cached_page = get_cached_data(XBZRLE.cache, current_addr); > > /* save current buffer into memory */ > @@ -736,7 +752,6 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data, > qemu_put_be16(rs->f, encoded_size); > qemu_put_buffer(rs->f, XBZRLE.encoded_buf, encoded_size); > bytes_xbzrle += encoded_size + 1 + 2; > - xbzrle_counters.pages++; > xbzrle_counters.encoded_size += encoded_size; > ram_counters.transferred += bytes_xbzrle; > > @@ -859,7 +874,7 @@ uint64_t ram_get_total_transferred_pages(void) > static void migration_update_rates(RAMState *rs, int64_t end_time) > { > uint64_t page_count = rs->target_page_count - rs->target_page_count_prev; > - double compressed_size; > + double compressed_size, encoded_size, unencoded_size; > > /* calculate period counters */ > ram_counters.dirty_pages_rate = rs->num_dirty_pages_period * 1000 > @@ -873,6 +888,18 @@ static void migration_update_rates(RAMState *rs, int64_t end_time) > xbzrle_counters.cache_miss_rate = (double)(xbzrle_counters.cache_miss - > rs->xbzrle_cache_miss_prev) / page_count; > rs->xbzrle_cache_miss_prev = xbzrle_counters.cache_miss; > + unencoded_size = (xbzrle_counters.pages - rs->xbzrle_pages_prev) * > + TARGET_PAGE_SIZE; > + encoded_size = xbzrle_counters.encoded_size - rs->encoded_size_prev; > + if (xbzrle_counters.pages == rs->xbzrle_pages_prev) { > + xbzrle_counters.encoding_rate = 0; > + } else if (!encoded_size) { > + xbzrle_counters.encoding_rate = UINT64_MAX; > + } else { > + xbzrle_counters.encoding_rate = unencoded_size / encoded_size; > + } > + rs->xbzrle_pages_prev = xbzrle_counters.pages; > + rs->encoded_size_prev = xbzrle_counters.encoded_size; > } > > if (migrate_use_compression()) { > diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c > index 6d3b35ca64..07f41e582f 100644 > --- a/monitor/hmp-cmds.c > +++ b/monitor/hmp-cmds.c > @@ -303,6 +303,8 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict) > info->xbzrle_cache->cache_miss); > monitor_printf(mon, "xbzrle cache miss rate: %0.2f\n", > info->xbzrle_cache->cache_miss_rate); > + monitor_printf(mon, "xbzrle encoding rate: %0.2f\n", > + info->xbzrle_cache->encoding_rate); > monitor_printf(mon, "xbzrle overflow: %" PRIu64 "\n", > info->xbzrle_cache->overflow); > } > diff --git a/qapi/migration.json b/qapi/migration.json > index bf195ff6ac..ee4513c565 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -70,6 +70,8 @@ > # > # @cache-miss-rate: rate of cache miss (since 2.1) > # > +# @encoding-rate: rate of cache miss > +# > # @overflow: number of overflows > # > # Since: 1.2 > @@ -77,7 +79,7 @@ > { 'struct': 'XBZRLECacheStats', > 'data': {'cache-size': 'int', 'encoded_size': 'int', 'pages': 'int', > 'cache-miss': 'int', 'cache-miss-rate': 'number', > - 'overflow': 'int' } } > + 'encoding-rate': 'number', 'overflow': 'int' } } > > ## > # @CompressionStats: > @@ -337,6 +339,7 @@ > # "pages":2444343, > # "cache-miss":2244, > # "cache-miss-rate":0.123, > +# "encoding-rate":80.1, > # "overflow":34434 > # } > # } > diff --git a/slirp b/slirp > index 55ab21c9a3..126c04acba 160000 > --- a/slirp > +++ b/slirp > @@ -1 +1 @@ > -Subproject commit 55ab21c9a36852915b81f1b41ebaf3b6509dd8ba > +Subproject commit 126c04acbabd7ad32c2b018fe10dfac2a3bc1210 Accidental inclusion of submodule changes Regards, Daniel
On 4/19/20 10:06 PM, Wei Wang wrote: > Users may need to check the xbzrle encoding rate to know if the guest > memory is xbzrle encoding-friendly, and dynamically turn off the > encoding if the encoding rate is low. > > Signed-off-by: Yi Sun <yi.y.sun@intel.com> > Signed-off-by: Wei Wang <wei.w.wang@intel.com> > --- In addition to Dan's review comments, > +++ b/qapi/migration.json > @@ -70,6 +70,8 @@ > # > # @cache-miss-rate: rate of cache miss (since 2.1) > # > +# @encoding-rate: rate of cache miss This is missing a '(since 5.1)' tag. > +# > # @overflow: number of overflows > # > # Since: 1.2 > @@ -77,7 +79,7 @@ > { 'struct': 'XBZRLECacheStats', > 'data': {'cache-size': 'int', 'encoded_size': 'int', 'pages': 'int', > 'cache-miss': 'int', 'cache-miss-rate': 'number', > - 'overflow': 'int' } } > + 'encoding-rate': 'number', 'overflow': 'int' } } > > ## > # @CompressionStats: > @@ -337,6 +339,7 @@ > # "pages":2444343, > # "cache-miss":2244, > # "cache-miss-rate":0.123, > +# "encoding-rate":80.1, > # "overflow":34434 > # } > # }
On 04/20/2020 10:53 PM, Eric Blake wrote: > On 4/19/20 10:06 PM, Wei Wang wrote: >> Users may need to check the xbzrle encoding rate to know if the guest >> memory is xbzrle encoding-friendly, and dynamically turn off the >> encoding if the encoding rate is low. >> >> Signed-off-by: Yi Sun <yi.y.sun@intel.com> >> Signed-off-by: Wei Wang <wei.w.wang@intel.com> >> --- > > In addition to Dan's review comments, > >> +++ b/qapi/migration.json >> @@ -70,6 +70,8 @@ >> # >> # @cache-miss-rate: rate of cache miss (since 2.1) >> # >> +# @encoding-rate: rate of cache miss > > This is missing a '(since 5.1)' tag. OK, will add it, thanks. Best, Wei
diff --git a/migration/migration.c b/migration/migration.c index 8e7ee0d76b..84a556a4ac 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -930,6 +930,7 @@ static void populate_ram_info(MigrationInfo *info, MigrationState *s) info->xbzrle_cache->pages = xbzrle_counters.pages; info->xbzrle_cache->cache_miss = xbzrle_counters.cache_miss; info->xbzrle_cache->cache_miss_rate = xbzrle_counters.cache_miss_rate; + info->xbzrle_cache->encoding_rate = xbzrle_counters.encoding_rate; info->xbzrle_cache->overflow = xbzrle_counters.overflow; } diff --git a/migration/ram.c b/migration/ram.c index bca5878f25..c87c38ec80 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -327,6 +327,10 @@ struct RAMState { uint64_t num_dirty_pages_period; /* xbzrle misses since the beginning of the period */ uint64_t xbzrle_cache_miss_prev; + /* Amount of xbzrle pages since the beginning of the period */ + uint64_t xbzrle_pages_prev; + /* Amount of encoded bytes since the beginning of the period */ + uint64_t encoded_size_prev; /* compression statistics since the beginning of the period */ /* amount of count that no free thread to compress data */ @@ -696,6 +700,18 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data, return -1; } + /* + * Reaching here means the page has hit the xbzrle cache, no matter what + * encoding result it is (normal encoding, overflow or skipping the page), + * count the page as encoded. This is used to caculate the encoding rate. + * + * Example: 2 pages (8KB) being encoded, first page encoding generates 2KB, + * 2nd page turns out to be skipped (i.e. no new bytes written to the + * page), the overall encoding rate will be 8KB / 2KB = 4, which has the + * skipped page included. In this way, the encoding rate can tell if the + * guest page is good for xbzrle encoding. + */ + xbzrle_counters.pages++; prev_cached_page = get_cached_data(XBZRLE.cache, current_addr); /* save current buffer into memory */ @@ -736,7 +752,6 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data, qemu_put_be16(rs->f, encoded_size); qemu_put_buffer(rs->f, XBZRLE.encoded_buf, encoded_size); bytes_xbzrle += encoded_size + 1 + 2; - xbzrle_counters.pages++; xbzrle_counters.encoded_size += encoded_size; ram_counters.transferred += bytes_xbzrle; @@ -859,7 +874,7 @@ uint64_t ram_get_total_transferred_pages(void) static void migration_update_rates(RAMState *rs, int64_t end_time) { uint64_t page_count = rs->target_page_count - rs->target_page_count_prev; - double compressed_size; + double compressed_size, encoded_size, unencoded_size; /* calculate period counters */ ram_counters.dirty_pages_rate = rs->num_dirty_pages_period * 1000 @@ -873,6 +888,18 @@ static void migration_update_rates(RAMState *rs, int64_t end_time) xbzrle_counters.cache_miss_rate = (double)(xbzrle_counters.cache_miss - rs->xbzrle_cache_miss_prev) / page_count; rs->xbzrle_cache_miss_prev = xbzrle_counters.cache_miss; + unencoded_size = (xbzrle_counters.pages - rs->xbzrle_pages_prev) * + TARGET_PAGE_SIZE; + encoded_size = xbzrle_counters.encoded_size - rs->encoded_size_prev; + if (xbzrle_counters.pages == rs->xbzrle_pages_prev) { + xbzrle_counters.encoding_rate = 0; + } else if (!encoded_size) { + xbzrle_counters.encoding_rate = UINT64_MAX; + } else { + xbzrle_counters.encoding_rate = unencoded_size / encoded_size; + } + rs->xbzrle_pages_prev = xbzrle_counters.pages; + rs->encoded_size_prev = xbzrle_counters.encoded_size; } if (migrate_use_compression()) { diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c index 6d3b35ca64..07f41e582f 100644 --- a/monitor/hmp-cmds.c +++ b/monitor/hmp-cmds.c @@ -303,6 +303,8 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict) info->xbzrle_cache->cache_miss); monitor_printf(mon, "xbzrle cache miss rate: %0.2f\n", info->xbzrle_cache->cache_miss_rate); + monitor_printf(mon, "xbzrle encoding rate: %0.2f\n", + info->xbzrle_cache->encoding_rate); monitor_printf(mon, "xbzrle overflow: %" PRIu64 "\n", info->xbzrle_cache->overflow); } diff --git a/qapi/migration.json b/qapi/migration.json index bf195ff6ac..ee4513c565 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -70,6 +70,8 @@ # # @cache-miss-rate: rate of cache miss (since 2.1) # +# @encoding-rate: rate of cache miss +# # @overflow: number of overflows # # Since: 1.2 @@ -77,7 +79,7 @@ { 'struct': 'XBZRLECacheStats', 'data': {'cache-size': 'int', 'encoded_size': 'int', 'pages': 'int', 'cache-miss': 'int', 'cache-miss-rate': 'number', - 'overflow': 'int' } } + 'encoding-rate': 'number', 'overflow': 'int' } } ## # @CompressionStats: @@ -337,6 +339,7 @@ # "pages":2444343, # "cache-miss":2244, # "cache-miss-rate":0.123, +# "encoding-rate":80.1, # "overflow":34434 # } # } diff --git a/slirp b/slirp index 55ab21c9a3..126c04acba 160000 --- a/slirp +++ b/slirp @@ -1 +1 @@ -Subproject commit 55ab21c9a36852915b81f1b41ebaf3b6509dd8ba +Subproject commit 126c04acbabd7ad32c2b018fe10dfac2a3bc1210