@@ -560,6 +560,8 @@ void multifd_save_cleanup(void)
qemu_thread_join(&p->thread);
}
}
+ dsa_stop();
+ dsa_cleanup();
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
Error *local_err = NULL;
@@ -702,6 +704,7 @@ static void buffer_is_zero_use_cpu(MultiFDSendParams *p)
{
const void **buf = (const void **)p->addr;
assert(!migrate_use_main_zero_page());
+ assert(!dsa_is_running());
for (int i = 0; i < p->pages->num; i++) {
p->batch_task->results[i] = buffer_is_zero(buf[i], p->page_size);
@@ -710,15 +713,29 @@ static void buffer_is_zero_use_cpu(MultiFDSendParams *p)
static void set_normal_pages(MultiFDSendParams *p)
{
+ assert(migrate_use_main_zero_page());
+
for (int i = 0; i < p->pages->num; i++) {
p->batch_task->results[i] = false;
}
}
+static void buffer_is_zero_use_dsa(MultiFDSendParams *p)
+{
+ assert(!migrate_use_main_zero_page());
+ assert(dsa_is_running());
+
+ buffer_is_zero_dsa_batch_async(p->batch_task,
+ (const void **)p->addr,
+ p->pages->num,
+ p->page_size);
+}
+
static void multifd_zero_page_check(MultiFDSendParams *p)
{
/* older qemu don't understand zero page on multifd channel */
bool use_multifd_zero_page = !migrate_use_main_zero_page();
+ bool use_multifd_dsa_accel = dsa_is_running();
RAMBlock *rb = p->pages->block;
@@ -726,7 +743,9 @@ static void multifd_zero_page_check(MultiFDSendParams *p)
p->addr[i] = (ram_addr_t)(rb->host + p->pages->offset[i]);
}
- if (use_multifd_zero_page) {
+ if (use_multifd_dsa_accel && use_multifd_zero_page) {
+ buffer_is_zero_use_dsa(p);
+ } else if (use_multifd_zero_page) {
buffer_is_zero_use_cpu(p);
} else {
// No zero page checking. All pages are normal pages.
@@ -1001,11 +1020,15 @@ int multifd_save_setup(Error **errp)
int thread_count;
uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
uint8_t i;
+ const char *dsa_parameter = migrate_multifd_dsa_accel();
if (!migrate_multifd()) {
return 0;
}
+ dsa_init(dsa_parameter);
+ dsa_start();
+
thread_count = migrate_multifd_channels();
multifd_send_state = g_malloc0(sizeof(*multifd_send_state));
multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
@@ -1061,6 +1084,7 @@ int multifd_save_setup(Error **errp)
return ret;
}
}
+
return 0;
}
@@ -1138,6 +1162,8 @@ void multifd_load_cleanup(void)
qemu_thread_join(&p->thread);
}
+ dsa_stop();
+ dsa_cleanup();
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
@@ -1272,6 +1298,7 @@ int multifd_load_setup(Error **errp)
int thread_count;
uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
uint8_t i;
+ const char *dsa_parameter = migrate_multifd_dsa_accel();
/*
* Return successfully if multiFD recv state is already initialised
@@ -1281,6 +1308,9 @@ int multifd_load_setup(Error **errp)
return 0;
}
+ dsa_init(dsa_parameter);
+ dsa_start();
+
thread_count = migrate_multifd_channels();
multifd_recv_state = g_malloc0(sizeof(*multifd_recv_state));
multifd_recv_state->params = g_new0(MultiFDRecvParams, thread_count);
@@ -1317,6 +1347,7 @@ int multifd_load_setup(Error **errp)
return ret;
}
}
+
return 0;
}
Multifd sender path gets an array of pages queued by the migration thread. It performs zero page checking on every page in the array. The pages are classfied as either a zero page or a normal page. This change uses Intel DSA to offload the zero page checking from CPU to the DSA accelerator. The sender thread submits a batch of pages to DSA hardware and waits for the DSA completion thread to signal for work completion. Signed-off-by: Hao Xiang <hao.xiang@bytedance.com> --- migration/multifd.c | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-)