Message ID | 156478c0b13ea74783925bc6fc730452260c81dd.1626433753.git.huangy81@chinatelecom.cn |
---|---|
State | New |
Headers | show |
Series | support dirtyrate measurement with dirty bitmap | expand |
On Fri, Jul 16, 2021 at 07:13:47PM +0800, huangy81@chinatelecom.cn wrote: > +static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config) > +{ > + int64_t msec = 0; > + int64_t start_time; > + DirtyPageRecord dirty_pages; [1] > + > + dirtyrate_global_dirty_log_start(); > + > + /* > + * 1'round of log sync may return all 1 bits with > + * KVM_DIRTY_LOG_INITIALLY_SET enable > + * skip it unconditionally and start dirty tracking > + * from 2'round of log sync > + */ > + dirtyrate_global_dirty_log_sync(); > + > + /* > + * reset page protect manually and unconditionally. > + * this make sure kvm dirty log be cleared if > + * KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE cap is enabled. > + */ > + dirtyrate_manual_reset_protect(); > + [2] > + record_dirtypages_bitmap(&dirty_pages, true); [3] > + > + start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); > + DirtyStat.start_time = start_time / 1000; > + > + msec = config.sample_period_seconds * 1000; > + msec = set_sample_page_period(msec, start_time); > + DirtyStat.calc_time = msec / 1000; > + > + /* fetch dirty bitmap from kvm and stop dirty tracking */ I don't think it really fetched anything.. So I think we need: dirtyrate_global_dirty_log_sync(); It seems to be there in older versions but not in the latest two versions. Please still remember to smoke the patches before posting, because without the log sync we'll read nothing. > + dirtyrate_global_dirty_log_stop(); > + > + record_dirtypages_bitmap(&dirty_pages, false); [4] I think it's easier we take bql at [1]/[3] and release at [2]/[4], rather than taking it for every function. Then we can move the bql operations out of dirtyrate_global_dirty_log_stop() in this patch. Thanks, > + > + do_calculate_dirtyrate_bitmap(dirty_pages); > +}
在 2021/7/17 3:36, Peter Xu 写道: > On Fri, Jul 16, 2021 at 07:13:47PM +0800, huangy81@chinatelecom.cn wrote: >> +static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config) >> +{ >> + int64_t msec = 0; >> + int64_t start_time; >> + DirtyPageRecord dirty_pages; > > [1] > >> + >> + dirtyrate_global_dirty_log_start(); >> + >> + /* >> + * 1'round of log sync may return all 1 bits with >> + * KVM_DIRTY_LOG_INITIALLY_SET enable >> + * skip it unconditionally and start dirty tracking >> + * from 2'round of log sync >> + */ >> + dirtyrate_global_dirty_log_sync(); >> + >> + /* >> + * reset page protect manually and unconditionally. >> + * this make sure kvm dirty log be cleared if >> + * KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE cap is enabled. >> + */ >> + dirtyrate_manual_reset_protect(); >> + > > [2] > >> + record_dirtypages_bitmap(&dirty_pages, true); > > [3] > >> + >> + start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); >> + DirtyStat.start_time = start_time / 1000; >> + >> + msec = config.sample_period_seconds * 1000; >> + msec = set_sample_page_period(msec, start_time); >> + DirtyStat.calc_time = msec / 1000; >> + >> + /* fetch dirty bitmap from kvm and stop dirty tracking */ > > I don't think it really fetched anything.. So I think we need: > > dirtyrate_global_dirty_log_sync(); > > It seems to be there in older versions but not in the latest two versions. yes, latest version dropped this because dirtyrate_global_dirty_log_stop below already do the sync before stop dirty log, which is recommended in patchset of "support dirtyrate at the granualrity of vcpu" and make dirtyrate more accurate. the older version do not consider this. :) > > Please still remember to smoke the patches before posting, because without the > log sync we'll read nothing. > >> + dirtyrate_global_dirty_log_stop(); >> + >> + record_dirtypages_bitmap(&dirty_pages, false); > > [4] > > I think it's easier we take bql at [1]/[3] and release at [2]/[4], rather than > taking it for every function. Then we can move the bql operations out of > dirtyrate_global_dirty_log_stop() in this patch. yeah, take bql at [1] and release at [2] is reasonable. but if we try to take bql at [3], it will sleep for calculation time in set_sample_page_period which is configured by user, which may be a heavy overhead. how about we take bql at [1] and release at [2], ingore bql at [3]/[4] and let it be the same as older versoin. since we only copy total_dirty_pages to local var in "get_dirtyrate" thread and maybe we don't need bql. > > Thanks, > >> + >> + do_calculate_dirtyrate_bitmap(dirty_pages); >> +} >
On Sat, Jul 17, 2021 at 10:57:50AM +0800, Hyman wrote: > > > 在 2021/7/17 3:36, Peter Xu 写道: > > On Fri, Jul 16, 2021 at 07:13:47PM +0800, huangy81@chinatelecom.cn wrote: > > > +static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config) > > > +{ > > > + int64_t msec = 0; > > > + int64_t start_time; > > > + DirtyPageRecord dirty_pages; > > > > [1] > > > > > + > > > + dirtyrate_global_dirty_log_start(); > > > + > > > + /* > > > + * 1'round of log sync may return all 1 bits with > > > + * KVM_DIRTY_LOG_INITIALLY_SET enable > > > + * skip it unconditionally and start dirty tracking > > > + * from 2'round of log sync > > > + */ > > > + dirtyrate_global_dirty_log_sync(); > > > + > > > + /* > > > + * reset page protect manually and unconditionally. > > > + * this make sure kvm dirty log be cleared if > > > + * KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE cap is enabled. > > > + */ > > > + dirtyrate_manual_reset_protect(); > > > + > > > > [2] > > > > > + record_dirtypages_bitmap(&dirty_pages, true); > > > > [3] > > > > > + > > > + start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); > > > + DirtyStat.start_time = start_time / 1000; > > > + > > > + msec = config.sample_period_seconds * 1000; > > > + msec = set_sample_page_period(msec, start_time); > > > + DirtyStat.calc_time = msec / 1000; > > > + > > > + /* fetch dirty bitmap from kvm and stop dirty tracking */ > > > > I don't think it really fetched anything.. So I think we need: > > > > dirtyrate_global_dirty_log_sync(); > > > > It seems to be there in older versions but not in the latest two versions. > yes, latest version dropped this because dirtyrate_global_dirty_log_stop > below already do the sync before stop dirty log, which is recommended in > patchset of "support dirtyrate at the granualrity of vcpu" and make > dirtyrate more accurate. the older version do not consider this. :) Oh I see. I was still using your old code so it does not have that bit. It's okay. > > > > Please still remember to smoke the patches before posting, because without the > > log sync we'll read nothing. > > > > > + dirtyrate_global_dirty_log_stop(); > > > + > > > + record_dirtypages_bitmap(&dirty_pages, false); > > > > [4] > > > > I think it's easier we take bql at [1]/[3] and release at [2]/[4], rather than > > taking it for every function. Then we can move the bql operations out of > > dirtyrate_global_dirty_log_stop() in this patch. > yeah, take bql at [1] and release at [2] is reasonable. > but if we try to take bql at [3], it will sleep for calculation time in > set_sample_page_period which is configured by user, which may be a heavy > overhead. > how about we take bql at [1] and release at [2], ingore bql at [3]/[4] and > let it be the same as older versoin. since we only copy total_dirty_pages to > local var in "get_dirtyrate" thread and maybe we don't need bql. Sounds good, thanks.
diff --git a/hmp-commands.hx b/hmp-commands.hx index f7fc9d7..605973c 100644 --- a/hmp-commands.hx +++ b/hmp-commands.hx @@ -1738,9 +1738,10 @@ ERST { .name = "calc_dirty_rate", - .args_type = "dirty_ring:-r,second:l,sample_pages_per_GB:l?", - .params = "[-r] second [sample_pages_per_GB]", - .help = "start a round of guest dirty rate measurement (using -d to" - "\n\t\t\t specify dirty ring as the method of calculation)", + .args_type = "dirty_ring:-r,dirty_bitmap:-b,second:l,sample_pages_per_GB:l?", + .params = "[-r] [-b] second [sample_pages_per_GB]", + .help = "start a round of guest dirty rate measurement (using -r to" + "\n\t\t\t specify dirty ring as the method of calculation and" + "\n\t\t\t -b to specify dirty bitmap as method of calculation)", .cmd = hmp_calc_dirty_rate, }, diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c index 17b3d2c..f9e4c03 100644 --- a/migration/dirtyrate.c +++ b/migration/dirtyrate.c @@ -15,6 +15,7 @@ #include "qapi/error.h" #include "cpu.h" #include "exec/ramblock.h" +#include "exec/ram_addr.h" #include "qemu/rcu_queue.h" #include "qemu/main-loop.h" #include "qapi/qapi-commands-migration.h" @@ -118,6 +119,10 @@ static struct DirtyRateInfo *query_dirty_rate_info(void) } info->vcpu_dirty_rate = head; } + + if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) { + info->sample_pages = 0; + } } trace_query_dirty_rate_info(DirtyRateStatus_str(CalculatingState)); @@ -416,6 +421,13 @@ static void dirtyrate_global_dirty_log_stop(void) qemu_mutex_unlock_iothread(); } +static void dirtyrate_global_dirty_log_sync(void) +{ + qemu_mutex_lock_iothread(); + memory_global_dirty_log_sync(); + qemu_mutex_unlock_iothread(); +} + static int64_t do_calculate_dirtyrate_vcpu(DirtyPageRecord dirty_pages) { uint64_t memory_size_MB; @@ -429,6 +441,75 @@ static int64_t do_calculate_dirtyrate_vcpu(DirtyPageRecord dirty_pages) return memory_size_MB / time_s; } +static inline void record_dirtypages_bitmap(DirtyPageRecord *dirty_pages, + bool start) +{ + if (start) { + dirty_pages->start_pages = total_dirty_pages; + } else { + dirty_pages->end_pages = total_dirty_pages; + } +} + +static void do_calculate_dirtyrate_bitmap(DirtyPageRecord dirty_pages) +{ + DirtyStat.dirty_rate = do_calculate_dirtyrate_vcpu(dirty_pages); +} + +static inline void dirtyrate_manual_reset_protect(void) +{ + RAMBlock *block = NULL; + + qemu_mutex_lock_iothread(); + WITH_RCU_READ_LOCK_GUARD() { + RAMBLOCK_FOREACH_MIGRATABLE(block) { + memory_region_clear_dirty_bitmap(block->mr, 0, + block->used_length); + } + } + qemu_mutex_unlock_iothread(); +} + +static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config) +{ + int64_t msec = 0; + int64_t start_time; + DirtyPageRecord dirty_pages; + + dirtyrate_global_dirty_log_start(); + + /* + * 1'round of log sync may return all 1 bits with + * KVM_DIRTY_LOG_INITIALLY_SET enable + * skip it unconditionally and start dirty tracking + * from 2'round of log sync + */ + dirtyrate_global_dirty_log_sync(); + + /* + * reset page protect manually and unconditionally. + * this make sure kvm dirty log be cleared if + * KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE cap is enabled. + */ + dirtyrate_manual_reset_protect(); + + record_dirtypages_bitmap(&dirty_pages, true); + + start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); + DirtyStat.start_time = start_time / 1000; + + msec = config.sample_period_seconds * 1000; + msec = set_sample_page_period(msec, start_time); + DirtyStat.calc_time = msec / 1000; + + /* fetch dirty bitmap from kvm and stop dirty tracking */ + dirtyrate_global_dirty_log_stop(); + + record_dirtypages_bitmap(&dirty_pages, false); + + do_calculate_dirtyrate_bitmap(dirty_pages); +} + static void calculate_dirtyrate_dirty_ring(struct DirtyRateConfig config) { CPUState *cpu; @@ -514,7 +595,9 @@ out: static void calculate_dirtyrate(struct DirtyRateConfig config) { - if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) { + if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) { + calculate_dirtyrate_dirty_bitmap(config); + } else if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) { calculate_dirtyrate_dirty_ring(config); } else { calculate_dirtyrate_sample_vm(config); @@ -597,12 +680,15 @@ void qmp_calc_dirty_rate(int64_t calc_time, /* * dirty ring mode only works when kvm dirty ring is enabled. + * on the contrary, dirty bitmap mode is not. */ - if ((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) && - !kvm_dirty_ring_enabled()) { - error_setg(errp, "dirty ring is disabled, use sample-pages method " - "or remeasure later."); - return; + if (((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) && + !kvm_dirty_ring_enabled()) || + ((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) && + kvm_dirty_ring_enabled())) { + error_setg(errp, "mode %s is not enabled, use other method instead.", + DirtyRateMeasureMode_str(mode)); + return; } /* @@ -678,9 +764,8 @@ void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict) int64_t sample_pages = qdict_get_try_int(qdict, "sample_pages_per_GB", -1); bool has_sample_pages = (sample_pages != -1); bool dirty_ring = qdict_get_try_bool(qdict, "dirty_ring", false); - DirtyRateMeasureMode mode = - (dirty_ring ? DIRTY_RATE_MEASURE_MODE_DIRTY_RING : - DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING); + bool dirty_bitmap = qdict_get_try_bool(qdict, "dirty_bitmap", false); + DirtyRateMeasureMode mode = DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING; Error *err = NULL; if (!sec) { @@ -688,6 +773,18 @@ void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict) return; } + if (dirty_ring && dirty_bitmap) { + monitor_printf(mon, "Either dirty ring or dirty bitmap " + "can be specified!\n"); + return; + } + + if (dirty_bitmap) { + mode = DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP; + } else if (dirty_ring) { + mode = DIRTY_RATE_MEASURE_MODE_DIRTY_RING; + } + qmp_calc_dirty_rate(sec, has_sample_pages, sample_pages, true, mode, &err); if (err) { diff --git a/qapi/migration.json b/qapi/migration.json index de35528..0b00976 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -1747,13 +1747,15 @@ # # @page-sampling: calculate dirtyrate by sampling pages. # -# @dirty-ring: calculate dirtyrate by via dirty ring. +# @dirty-ring: calculate dirtyrate by dirty ring. +# +# @dirty-bitmap: calculate dirtyrate by dirty bitmap. # # Since: 6.1 # ## { 'enum': 'DirtyRateMeasureMode', - 'data': ['page-sampling', 'dirty-ring'] } + 'data': ['page-sampling', 'dirty-ring', 'dirty-bitmap'] } ## # @DirtyRateInfo: