diff options
| author | Michael R. Hines <mrhines@us.ibm.com> | 2013-06-25 21:35:36 -0400 |
|---|---|---|
| committer | Juan Quintela <quintela@redhat.com> | 2013-06-27 02:38:36 +0200 |
| commit | 60d9222c8f50c3e5dd3df9ee84ddd1d1c4b35389 (patch) | |
| tree | e15ec28f02b7d995171274aa47703244880dd827 | |
| parent | 43487c678d6e4e7182bfa70d2bc75422578782aa (diff) | |
rdma: introduce capability x-rdma-pin-all
This capability allows you to disable dynamic chunk registration
for better throughput on high-performance links.
For example, using an 8GB RAM virtual machine with all 8GB of memory in
active use and the VM itself is completely idle using a 40 gbps infiniband link:
1. x-rdma-pin-all disabled total time: approximately 7.5 seconds @ 9.5 Gbps
2. x-rdma-pin-all enabled total time: approximately 4 seconds @ 26 Gbps
These numbers would of course scale up to whatever size virtual machine
you have to migrate using RDMA.
Enabling this feature does *not* have any measurable affect on
migration *downtime*. This is because, without this feature, all of the
memory will have already been registered already in advance during
the bulk round and does not need to be re-registered during the successive
iteration rounds.
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
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>
Signed-off-by: Juan Quintela <quintela@redhat.com>
| -rw-r--r-- | include/migration/migration.h | 2 | ||||
| -rw-r--r-- | migration.c | 9 | ||||
| -rw-r--r-- | qapi-schema.json | 7 |
3 files changed, 17 insertions, 1 deletions
diff --git a/include/migration/migration.h b/include/migration/migration.h index 3ddd64ffcb..f0640e0eec 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -123,6 +123,8 @@ void migrate_add_blocker(Error *reason); */ void migrate_del_blocker(Error *reason); +bool migrate_rdma_pin_all(void); + int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen, uint8_t *dst, int dlen); int xbzrle_decode_buffer(uint8_t *src, int slen, uint8_t *dst, int dlen); diff --git a/migration.c b/migration.c index 441a3b23f9..a704d48669 100644 --- a/migration.c +++ b/migration.c @@ -476,6 +476,15 @@ void qmp_migrate_set_downtime(double value, Error **errp) max_downtime = (uint64_t)value; } +bool migrate_rdma_pin_all(void) +{ + MigrationState *s; + + s = migrate_get_current(); + + return s->enabled_capabilities[MIGRATION_CAPABILITY_X_RDMA_PIN_ALL]; +} + int migrate_use_xbzrle(void) { MigrationState *s; diff --git a/qapi-schema.json b/qapi-schema.json index 78da5577af..a30a728dde 100644 --- a/qapi-schema.json +++ b/qapi-schema.json @@ -608,10 +608,15 @@ # This feature allows us to minimize migration traffic for certain work # loads, by sending compressed difference of the pages # +# @x-rdma-pin-all: Controls whether or not the entire VM memory footprint is +# mlock()'d on demand or all at once. Refer to docs/rdma.txt for usage. +# Disabled by default. Experimental: may (or may not) be renamed after +# further testing is complete. (since 1.6) +# # Since: 1.2 ## { 'enum': 'MigrationCapability', - 'data': ['xbzrle'] } + 'data': ['xbzrle', 'x-rdma-pin-all'] } ## # @MigrationCapabilityStatus |