Re: [Qemu-devel] [PATCH v10 14/14, resend] rdma: add setup time accounting to QMP statistics

["Michael R. Hines" <mrhines@linux.vnet.ibm.com>]

On 06/24/2013 09:51 AM, Paolo Bonzini wrote:
> Il 24/06/2013 15:46, mrhines@linux.vnet.ibm.com ha scritto:
>> From: "Michael R. Hines" <mrhines@us.ibm.com>
>>
>> For very large virtual machines, pinning can take a long time.
>> While this does not affect the migration's *actual* time itself,
>> it is still important for the user to know what's going on and
>> to know what component of the total time is actual taken up by
>> pinning.
>>
>> For example, using a 14GB virtual machine, pinning can take as
>> long as 5 seconds, for which the user would not otherwise know
>> what was happening.
>>
>> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> Please stop inventing Reviewed-by tags, or I will stop reviewing your
> patches.
>
> Paolo

Inventing? I don't understand.

I accumulated all of those tags from everybody - copy and pasted 
directly from everyone when they gave them to me.\

What exactly is wrong here?

- Michael


>> Reviewed-by: Chegu Vinod <chegu_vinod@hp.com>
>> Reviewed-by: Eric Blake <eblake@redhat.com>
>> Tested-by: Chegu Vinod <chegu_vinod@hp.com>
>> Tested-by: Michael R. Hines <mrhines@us.ibm.com>
>> Signed-off-by: Michael R. Hines <mrhines@us.ibm.com>
>> ---
>>   hmp.c                         |   10 ++++++--
>>   include/migration/migration.h |    1 +
>>   migration-rdma.c              |   51 +++++++++++++++++++++++------------------
>>   migration.c                   |   41 +++++++++++++++++++++++----------
>>   qapi-schema.json              |   13 ++++++++---
>>   5 files changed, 77 insertions(+), 39 deletions(-)
>>
>> diff --git a/hmp.c b/hmp.c
>> index 148a3fb..2b75b28 100644
>> --- a/hmp.c
>> +++ b/hmp.c
>> @@ -154,8 +154,10 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
>>   
>>       if (info->has_status) {
>>           monitor_printf(mon, "Migration status: %s\n", info->status);
>> -        monitor_printf(mon, "total time: %" PRIu64 " milliseconds\n",
>> -                       info->total_time);
>> +        if (info->has_total_time) {
>> +            monitor_printf(mon, "total time: %" PRIu64 " milliseconds\n",
>> +                           info->total_time);
>> +        }
>>           if (info->has_expected_downtime) {
>>               monitor_printf(mon, "expected downtime: %" PRIu64 " milliseconds\n",
>>                              info->expected_downtime);
>> @@ -164,6 +166,10 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
>>               monitor_printf(mon, "downtime: %" PRIu64 " milliseconds\n",
>>                              info->downtime);
>>           }
>> +        if (info->has_setup_time) {
>> +            monitor_printf(mon, "setup: %" PRIu64 " milliseconds\n",
>> +                           info->setup_time);
>> +        }
>>       }
>>   
>>       if (info->has_ram) {
>> diff --git a/include/migration/migration.h b/include/migration/migration.h
>> index b49e68b..82e8713 100644
>> --- a/include/migration/migration.h
>> +++ b/include/migration/migration.h
>> @@ -49,6 +49,7 @@ struct MigrationState
>>       bool enabled_capabilities[MIGRATION_CAPABILITY_MAX];
>>       int64_t xbzrle_cache_size;
>>       double mbps;
>> +    int64_t setup_time;
>>   };
>>   
>>   void process_incoming_migration(QEMUFile *f);
>> diff --git a/migration-rdma.c b/migration-rdma.c
>> index 853de18..165297e 100644
>> --- a/migration-rdma.c
>> +++ b/migration-rdma.c
>> @@ -699,12 +699,10 @@ static int qemu_rdma_alloc_qp(RDMAContext *rdma)
>>       return 0;
>>   }
>>   
>> -static int qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma,
>> -                                RDMALocalBlocks *rdma_local_ram_blocks)
>> +static int qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma)
>>   {
>>       int i;
>> -    uint64_t start = qemu_get_clock_ms(rt_clock);
>> -    (void)start;
>> +    RDMALocalBlocks *rdma_local_ram_blocks = &rdma->local_ram_blocks;
>>   
>>       for (i = 0; i < rdma_local_ram_blocks->num_blocks; i++) {
>>           rdma_local_ram_blocks->block[i].mr =
>> @@ -721,8 +719,6 @@ static int qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma,
>>           rdma->total_registrations++;
>>       }
>>   
>> -    DPRINTF("lock time: %" PRIu64 "\n", qemu_get_clock_ms(rt_clock) - start);
>> -
>>       if (i >= rdma_local_ram_blocks->num_blocks) {
>>           return 0;
>>       }
>> @@ -1262,7 +1258,8 @@ static void qemu_rdma_move_header(RDMAContext *rdma, int idx,
>>    */
>>   static int qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader *head,
>>                                      uint8_t *data, RDMAControlHeader *resp,
>> -                                   int *resp_idx)
>> +                                   int *resp_idx,
>> +                                   int (*callback)(RDMAContext *rdma))
>>   {
>>       int ret = 0;
>>       int idx = 0;
>> @@ -1315,6 +1312,14 @@ static int qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader *head,
>>        * If we're expecting a response, block and wait for it.
>>        */
>>       if (resp) {
>> +        if (callback) {
>> +            DPRINTF("Issuing callback before receiving response...\n");
>> +            ret = callback(rdma);
>> +            if (ret < 0) {
>> +                return ret;
>> +            }
>> +        }
>> +
>>           DDPRINTF("Waiting for response %s\n", control_desc[resp->type]);
>>           ret = qemu_rdma_exchange_get_response(rdma, resp, resp->type, idx + 1);
>>   
>> @@ -1464,7 +1469,7 @@ static int qemu_rdma_write_one(QEMUFile *f, RDMAContext *rdma,
>>                       chunk, sge.length, current_index, offset);
>>   
>>                   ret = qemu_rdma_exchange_send(rdma, &head,
>> -                                (uint8_t *) &comp, NULL, NULL);
>> +                                (uint8_t *) &comp, NULL, NULL, NULL);
>>   
>>                   if (ret < 0) {
>>                       return -EIO;
>> @@ -1487,7 +1492,7 @@ static int qemu_rdma_write_one(QEMUFile *f, RDMAContext *rdma,
>>                       chunk, sge.length, current_index, offset);
>>   
>>               ret = qemu_rdma_exchange_send(rdma, &head, (uint8_t *) &reg,
>> -                                    &resp, &reg_result_idx);
>> +                                    &resp, &reg_result_idx, NULL);
>>               if (ret < 0) {
>>                   return ret;
>>               }
>> @@ -2126,7 +2131,7 @@ static int qemu_rdma_put_buffer(void *opaque, const uint8_t *buf,
>>           head.len = r->len;
>>           head.type = RDMA_CONTROL_QEMU_FILE;
>>   
>> -        ret = qemu_rdma_exchange_send(rdma, &head, data, NULL, NULL);
>> +        ret = qemu_rdma_exchange_send(rdma, &head, data, NULL, NULL, NULL);
>>   
>>           if (ret < 0) {
>>               rdma->error_state = ret;
>> @@ -2482,7 +2487,7 @@ static int qemu_rdma_registration_handle(QEMUFile *f, void *opaque,
>>               DPRINTF("Initial setup info requested.\n");
>>   
>>               if (rdma->pin_all) {
>> -                ret = qemu_rdma_reg_whole_ram_blocks(rdma, &rdma->local_ram_blocks);
>> +                ret = qemu_rdma_reg_whole_ram_blocks(rdma);
>>                   if (ret) {
>>                       fprintf(stderr, "rdma migration: error dest "
>>                                       "registering ram blocks!\n");
>> @@ -2617,7 +2622,17 @@ static int qemu_rdma_registration_stop(QEMUFile *f, void *opaque,
>>           head.type = RDMA_CONTROL_RAM_BLOCKS_REQUEST;
>>           DPRINTF("Sending registration setup for ram blocks...\n");
>>   
>> -        ret = qemu_rdma_exchange_send(rdma, &head, NULL, &resp, &reg_result_idx);
>> +        /*
>> +         * Make sure that we parallelize the pinning on both sides.
>> +         * For very large guests, doing this serially takes a really
>> +         * long time, so we have to 'interleave' the pinning locally
>> +         * with the control messages by performing the pinning on this
>> +         * side before we receive the control response from the other
>> +         * side that the pinning has completed.
>> +         */
>> +        ret = qemu_rdma_exchange_send(rdma, &head, NULL, &resp,
>> +                    &reg_result_idx, rdma->pin_all ?
>> +                    qemu_rdma_reg_whole_ram_blocks : NULL);
>>           if (ret < 0) {
>>               ERROR(errp, "receiving remote info!\n");
>>               return ret;
>> @@ -2633,14 +2648,7 @@ static int qemu_rdma_registration_stop(QEMUFile *f, void *opaque,
>>               return ret;
>>           }
>>   
>> -        if (rdma->pin_all) {
>> -            ret = qemu_rdma_reg_whole_ram_blocks(rdma, &rdma->local_ram_blocks);
>> -            if (ret) {
>> -                fprintf(stderr, "rdma migration: error source "
>> -                                "registering ram blocks!\n");
>> -                return ret;
>> -            }
>> -        } else {
>> +        if (!rdma->pin_all) {
>>               int x = 0;
>>               for (x = 0; x < rdma->local_ram_blocks.num_blocks; x++) {
>>                   RDMALocalBlock *block = &(rdma->local_ram_blocks.block[x]);
>> @@ -2653,7 +2661,7 @@ static int qemu_rdma_registration_stop(QEMUFile *f, void *opaque,
>>       DDDPRINTF("Sending registration finish %" PRIu64 "...\n", flags);
>>   
>>       head.type = RDMA_CONTROL_REGISTER_FINISHED;
>> -    ret = qemu_rdma_exchange_send(rdma, &head, NULL, NULL, NULL);
>> +    ret = qemu_rdma_exchange_send(rdma, &head, NULL, NULL, NULL, NULL);
>>   
>>       if (ret < 0) {
>>           goto err;
>> @@ -2802,7 +2810,6 @@ void rdma_start_outgoing_migration(void *opaque,
>>       DPRINTF("qemu_rdma_source_connect success\n");
>>   
>>       s->file = qemu_fopen_rdma(rdma, "wb");
>> -    s->total_time = qemu_get_clock_ms(rt_clock);
>>       migrate_fd_connect(s);
>>       return;
>>   err:
>> diff --git a/migration.c b/migration.c
>> index 62c6b85..bb412df 100644
>> --- a/migration.c
>> +++ b/migration.c
>> @@ -36,7 +36,8 @@
>>   #endif
>>   
>>   enum {
>> -    MIG_STATE_ERROR,
>> +    MIG_STATE_ERROR = -1,
>> +    MIG_STATE_NONE,
>>       MIG_STATE_SETUP,
>>       MIG_STATE_CANCELLED,
>>       MIG_STATE_ACTIVE,
>> @@ -63,7 +64,7 @@ static NotifierList migration_state_notifiers =
>>   MigrationState *migrate_get_current(void)
>>   {
>>       static MigrationState current_migration = {
>> -        .state = MIG_STATE_SETUP,
>> +        .state = MIG_STATE_NONE,
>>           .bandwidth_limit = MAX_THROTTLE,
>>           .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
>>           .mbps = -1,
>> @@ -184,9 +185,14 @@ MigrationInfo *qmp_query_migrate(Error **errp)
>>       MigrationState *s = migrate_get_current();
>>   
>>       switch (s->state) {
>> -    case MIG_STATE_SETUP:
>> +    case MIG_STATE_NONE:
>>           /* no migration has happened ever */
>>           break;
>> +    case MIG_STATE_SETUP:
>> +        info->has_status = true;
>> +        info->status = g_strdup("setup");
>> +        info->has_total_time = false;
>> +        break;
>>       case MIG_STATE_ACTIVE:
>>           info->has_status = true;
>>           info->status = g_strdup("active");
>> @@ -195,6 +201,8 @@ MigrationInfo *qmp_query_migrate(Error **errp)
>>               - s->total_time;
>>           info->has_expected_downtime = true;
>>           info->expected_downtime = s->expected_downtime;
>> +        info->has_setup_time = true;
>> +        info->setup_time = s->setup_time;
>>   
>>           info->has_ram = true;
>>           info->ram = g_malloc0(sizeof(*info->ram));
>> @@ -226,6 +234,8 @@ MigrationInfo *qmp_query_migrate(Error **errp)
>>           info->total_time = s->total_time;
>>           info->has_downtime = true;
>>           info->downtime = s->downtime;
>> +        info->has_setup_time = true;
>> +        info->setup_time = s->setup_time;
>>   
>>           info->has_ram = true;
>>           info->ram = g_malloc0(sizeof(*info->ram));
>> @@ -257,7 +267,7 @@ void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
>>       MigrationState *s = migrate_get_current();
>>       MigrationCapabilityStatusList *cap;
>>   
>> -    if (s->state == MIG_STATE_ACTIVE) {
>> +    if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP) {
>>           error_set(errp, QERR_MIGRATION_ACTIVE);
>>           return;
>>       }
>> @@ -295,9 +305,9 @@ static void migrate_fd_cleanup(void *opaque)
>>       notifier_list_notify(&migration_state_notifiers, s);
>>   }
>>   
>> -static void migrate_finish_set_state(MigrationState *s, int new_state)
>> +static void migrate_set_state(MigrationState *s, int old_state, int new_state)
>>   {
>> -    if (__sync_val_compare_and_swap(&s->state, MIG_STATE_ACTIVE,
>> +    if (__sync_val_compare_and_swap(&s->state, old_state,
>>                                       new_state) == new_state) {
>>           trace_migrate_set_state(new_state);
>>       }
>> @@ -316,7 +326,8 @@ static void migrate_fd_cancel(MigrationState *s)
>>   {
>>       DPRINTF("cancelling migration\n");
>>   
>> -    migrate_finish_set_state(s, MIG_STATE_CANCELLED);
>> +    migrate_set_state(s, MIG_STATE_SETUP, MIG_STATE_CANCELLED);
>> +    migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_CANCELLED);
>>   }
>>   
>>   void add_migration_state_change_notifier(Notifier *notify)
>> @@ -393,7 +404,7 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
>>       params.blk = blk;
>>       params.shared = inc;
>>   
>> -    if (s->state == MIG_STATE_ACTIVE) {
>> +    if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP) {
>>           error_set(errp, QERR_MIGRATION_ACTIVE);
>>           return;
>>       }
>> @@ -517,6 +528,7 @@ static void *migration_thread(void *opaque)
>>   {
>>       MigrationState *s = opaque;
>>       int64_t initial_time = qemu_get_clock_ms(rt_clock);
>> +    int64_t setup_start = qemu_get_clock_ms(host_clock);
>>       int64_t initial_bytes = 0;
>>       int64_t max_size = 0;
>>       int64_t start_time = initial_time;
>> @@ -525,6 +537,11 @@ static void *migration_thread(void *opaque)
>>       DPRINTF("beginning savevm\n");
>>       qemu_savevm_state_begin(s->file, &s->params);
>>   
>> +    s->setup_time = qemu_get_clock_ms(host_clock) - setup_start;
>> +    migrate_set_state(s, MIG_STATE_SETUP, MIG_STATE_ACTIVE);
>> +
>> +    DPRINTF("setup complete\n");
>> +
>>       while (s->state == MIG_STATE_ACTIVE) {
>>           int64_t current_time;
>>           uint64_t pending_size;
>> @@ -546,14 +563,14 @@ static void *migration_thread(void *opaque)
>>                   qemu_savevm_state_complete(s->file);
>>                   qemu_mutex_unlock_iothread();
>>                   if (!qemu_file_get_error(s->file)) {
>> -                    migrate_finish_set_state(s, MIG_STATE_COMPLETED);
>> +                    migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_COMPLETED);
>>                       break;
>>                   }
>>               }
>>           }
>>   
>>           if (qemu_file_get_error(s->file)) {
>> -            migrate_finish_set_state(s, MIG_STATE_ERROR);
>> +            migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
>>               break;
>>           }
>>           current_time = qemu_get_clock_ms(rt_clock);
>> @@ -604,8 +621,8 @@ static void *migration_thread(void *opaque)
>>   
>>   void migrate_fd_connect(MigrationState *s)
>>   {
>> -    s->state = MIG_STATE_ACTIVE;
>> -    trace_migrate_set_state(MIG_STATE_ACTIVE);
>> +    s->state = MIG_STATE_SETUP;
>> +    trace_migrate_set_state(MIG_STATE_SETUP);
>>   
>>       /* This is a best 1st approximation. ns to ms */
>>       s->expected_downtime = max_downtime/1000000;
>> diff --git a/qapi-schema.json b/qapi-schema.json
>> index 4e9cd6d..69faaad 100644
>> --- a/qapi-schema.json
>> +++ b/qapi-schema.json
>> @@ -578,6 +578,12 @@
>>   #        expected downtime in milliseconds for the guest in last walk
>>   #        of the dirty bitmap. (since 1.3)
>>   #
>> +# @setup-time: #optional amount of setup time spent _before_ the iterations
>> +#        begin but _after_ the QMP command is issued. This is designed to
>> +#        provide an accounting of any activities (such as RDMA pinning) which
>> +#        may be expensive, but do not actually occur during the iterative
>> +#        migration rounds themselves. (since 1.6)
>> +#
>>   # Since: 0.14.0
>>   ##
>>   { 'type': 'MigrationInfo',
>> @@ -586,7 +592,8 @@
>>              '*xbzrle-cache': 'XBZRLECacheStats',
>>              '*total-time': 'int',
>>              '*expected-downtime': 'int',
>> -           '*downtime': 'int'} }
>> +           '*downtime': 'int',
>> +           '*setup-time' : 'int'} }
>>   
>>   ##
>>   # @query-migrate
>>