Message ID | 1372125485-11795-11-git-send-email-mrhines@linux.vnet.ibm.com |
---|---|
State | New |
Headers | show |
mrhines@linux.vnet.ibm.com wrote: > From: "Michael R. Hines" <mrhines@us.ibm.com> > > 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: 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> Reviewed-by: Juan Quintela <quintela@redhat.com>
diff --git a/include/migration/migration.h b/include/migration/migration.h index 7b153d7..9d3cc85 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -125,6 +125,8 @@ 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 441a3b2..a704d48 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 78da557..a30a728 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