During live migration, if the latency between sender and receiver
is high but bandwidth is 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.
Signed-off-by: Hao Xiang <hao.xi...@bytedance.com>
---
migration/migration-hmp-cmds.c | 7 +++++++
migration/multifd-zlib.c | 4 ++--
migration/multifd-zstd.c | 4 ++--
migration/multifd.c | 6 ++++--
migration/multifd.h | 3 ---
5 files changed, 15 insertions(+), 9 deletions(-)
diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
index e1f110afbc..c53e4d8543 100644
--- a/migration/migration-hmp-cmds.c
+++ b/migration/migration-hmp-cmds.c
@@ -333,6 +333,9 @@ 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);
@@ -597,6 +600,10 @@ 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..a1b127d0d1 100644
--- a/migration/multifd-zlib.c
+++ b/migration/multifd-zlib.c
@@ -58,7 +58,7 @@ 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(migrate_multifd_packet_size());
z->zbuff = g_try_malloc(z->zbuff_len);
if (!z->zbuff) {
err_msg = "out of memory for zbuff";
@@ -200,7 +200,7 @@ 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 = migrate_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..0c92112702 100644
--- a/migration/multifd-zstd.c
+++ b/migration/multifd-zstd.c
@@ -69,7 +69,7 @@ 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(migrate_multifd_packet_size());
z->zbuff = g_try_malloc(z->zbuff_len);
if (!z->zbuff) {
ZSTD_freeCStream(z->zcs);
@@ -196,7 +196,7 @@ 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 = migrate_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 a0bfb48a7e..a6ecfdd449 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -1045,7 +1045,8 @@ static void multifd_new_send_channel_async(QIOTask *task,
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();
@@ -1323,7 +1324,8 @@ 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();
diff --git a/migration/multifd.h b/migration/multifd.h
index 297b055e2b..8b1cf136d7 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
