During live migration, if the latency between sender and receiver is high and bandwidth is also high (a long and fat pipe), using a bigger packet size can help reduce migration total time. In addition, Intel DSA offloading performs better with a large batch task. Providing an option to set the packet size is useful for performance tuning.
Set the option: migrate_set_parameter multifd-packet-size 4190208 Signed-off-by: Hao Xiang <hao.xi...@bytedance.com> --- migration/migration-hmp-cmds.c | 7 +++++++ migration/multifd-zlib.c | 6 ++++-- migration/multifd-zstd.c | 6 ++++-- migration/multifd.c | 6 ++++-- migration/multifd.h | 3 --- 5 files changed, 19 insertions(+), 9 deletions(-) diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c index 8219d112d6..272b553c3a 100644 --- a/migration/migration-hmp-cmds.c +++ b/migration/migration-hmp-cmds.c @@ -338,6 +338,9 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict) monitor_printf(mon, "%s: %s\n", MigrationParameter_str(MIGRATION_PARAMETER_BLOCK_INCREMENTAL), params->block_incremental ? "on" : "off"); + monitor_printf(mon, "%s: %" PRIu64 "\n", + MigrationParameter_str(MIGRATION_PARAMETER_MULTIFD_PACKET_SIZE), + params->multifd_packet_size); monitor_printf(mon, "%s: %u\n", MigrationParameter_str(MIGRATION_PARAMETER_MULTIFD_CHANNELS), params->multifd_channels); @@ -626,6 +629,10 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict) p->multifd_dsa_accel->type = QTYPE_QSTRING; visit_type_str(v, param, &p->multifd_dsa_accel->u.s, &err); break; + case MIGRATION_PARAMETER_MULTIFD_PACKET_SIZE: + p->has_multifd_packet_size = true; + visit_type_size(v, param, &p->multifd_packet_size, &err); + break; case MIGRATION_PARAMETER_MULTIFD_CHANNELS: p->has_multifd_channels = true; visit_type_uint8(v, param, &p->multifd_channels, &err); diff --git a/migration/multifd-zlib.c b/migration/multifd-zlib.c index 37ce48621e..4318ccced8 100644 --- a/migration/multifd-zlib.c +++ b/migration/multifd-zlib.c @@ -49,6 +49,7 @@ static int zlib_send_setup(MultiFDSendParams *p, Error **errp) struct zlib_data *z = g_new0(struct zlib_data, 1); z_stream *zs = &z->zs; const char *err_msg; + uint64_t multifd_packet_size = migrate_multifd_packet_size(); zs->zalloc = Z_NULL; zs->zfree = Z_NULL; @@ -58,7 +59,7 @@ static int zlib_send_setup(MultiFDSendParams *p, Error **errp) goto err_free_z; } /* This is the maximum size of the compressed buffer */ - z->zbuff_len = compressBound(MULTIFD_PACKET_SIZE); + z->zbuff_len = compressBound(multifd_packet_size); z->zbuff = g_try_malloc(z->zbuff_len); if (!z->zbuff) { err_msg = "out of memory for zbuff"; @@ -186,6 +187,7 @@ static int zlib_send_prepare(MultiFDSendParams *p, Error **errp) */ static int zlib_recv_setup(MultiFDRecvParams *p, Error **errp) { + uint64_t multifd_packet_size = migrate_multifd_packet_size(); struct zlib_data *z = g_new0(struct zlib_data, 1); z_stream *zs = &z->zs; @@ -200,7 +202,7 @@ static int zlib_recv_setup(MultiFDRecvParams *p, Error **errp) return -1; } /* To be safe, we reserve twice the size of the packet */ - z->zbuff_len = MULTIFD_PACKET_SIZE * 2; + z->zbuff_len = multifd_packet_size * 2; z->zbuff = g_try_malloc(z->zbuff_len); if (!z->zbuff) { inflateEnd(zs); diff --git a/migration/multifd-zstd.c b/migration/multifd-zstd.c index b471daadcd..a6fdb2ac11 100644 --- a/migration/multifd-zstd.c +++ b/migration/multifd-zstd.c @@ -49,6 +49,7 @@ struct zstd_data { */ static int zstd_send_setup(MultiFDSendParams *p, Error **errp) { + uint64_t multifd_packet_size = migrate_multifd_packet_size(); struct zstd_data *z = g_new0(struct zstd_data, 1); int res; @@ -69,7 +70,7 @@ static int zstd_send_setup(MultiFDSendParams *p, Error **errp) return -1; } /* This is the maximum size of the compressed buffer */ - z->zbuff_len = ZSTD_compressBound(MULTIFD_PACKET_SIZE); + z->zbuff_len = ZSTD_compressBound(multifd_packet_size); z->zbuff = g_try_malloc(z->zbuff_len); if (!z->zbuff) { ZSTD_freeCStream(z->zcs); @@ -175,6 +176,7 @@ static int zstd_send_prepare(MultiFDSendParams *p, Error **errp) */ static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp) { + uint64_t multifd_packet_size = migrate_multifd_packet_size(); struct zstd_data *z = g_new0(struct zstd_data, 1); int ret; @@ -196,7 +198,7 @@ static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp) } /* To be safe, we reserve twice the size of the packet */ - z->zbuff_len = MULTIFD_PACKET_SIZE * 2; + z->zbuff_len = multifd_packet_size * 2; z->zbuff = g_try_malloc(z->zbuff_len); if (!z->zbuff) { ZSTD_freeDStream(z->zds); diff --git a/migration/multifd.c b/migration/multifd.c index cfae5401a9..700fb1c034 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -1046,7 +1046,8 @@ static void multifd_new_send_channel_create(gpointer opaque) int multifd_save_setup(Error **errp) { int thread_count; - uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size(); + uint32_t page_count = + migrate_multifd_packet_size() / qemu_target_page_size(); uint8_t i; const char *dsa_parameter = migrate_multifd_dsa_accel(); int ret; @@ -1327,7 +1328,8 @@ static void *multifd_recv_thread(void *opaque) int multifd_load_setup(Error **errp) { int thread_count; - uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size(); + uint32_t page_count = + migrate_multifd_packet_size() / qemu_target_page_size(); uint8_t i; const char *dsa_parameter = migrate_multifd_dsa_accel(); int ret; diff --git a/migration/multifd.h b/migration/multifd.h index 97b5f888a7..4f30b24832 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -34,9 +34,6 @@ int multifd_queue_page(QEMUFile *f, RAMBlock *block, ram_addr_t offset); #define MULTIFD_FLAG_ZLIB (1 << 1) #define MULTIFD_FLAG_ZSTD (2 << 1) -/* This value needs to be a multiple of qemu_target_page_size() */ -#define MULTIFD_PACKET_SIZE (512 * 1024) - typedef struct { uint32_t magic; uint32_t version; -- 2.30.2