diff mbox series

[v3,14/20] migration/multifd: Enable DSA offloading in multifd sender path.

Message ID 20240104004452.324068-15-hao.xiang@bytedance.com
State New
Headers show
Series Use Intel DSA accelerator to offload zero page checking in multifd live migration. | expand

Commit Message

Hao Xiang Jan. 4, 2024, 12:44 a.m. UTC 
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 | 51 ++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 46 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/migration/multifd.c b/migration/multifd.c
index e7c549b93e..6e73d995b0 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -560,6 +560,7 @@  void multifd_save_cleanup(void)
             qemu_thread_join(&p->thread);
         }
     }
+    dsa_cleanup();
     for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
         Error *local_err = NULL;
@@ -699,6 +700,7 @@  static void buffer_is_zero_use_cpu(MultiFDSendParams *p)
 {
     const void **buf = (const void **)p->batch_task->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);
@@ -707,15 +709,29 @@  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->batch_task->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;
 
@@ -723,7 +739,9 @@  static void multifd_zero_page_check(MultiFDSendParams *p)
         p->batch_task->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. */
@@ -997,11 +1015,23 @@  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();
+    int ret;
+    Error *local_err = NULL;
 
     if (!migrate_multifd()) {
         return 0;
     }
 
+    ret = dsa_init(dsa_parameter);
+    if (ret != 0) {
+        error_setg(&local_err, "multifd: Sender failed to initialize DSA.");
+        error_propagate(errp, local_err);
+        return ret;
+    }
+
+    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);
@@ -1046,8 +1076,6 @@  int multifd_save_setup(Error **errp)
 
     for (i = 0; i < thread_count; i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
-        Error *local_err = NULL;
-        int ret;
 
         ret = multifd_send_state->ops->send_setup(p, &local_err);
         if (ret) {
@@ -1055,6 +1083,7 @@  int multifd_save_setup(Error **errp)
             return ret;
         }
     }
+
     return 0;
 }
 
@@ -1132,6 +1161,7 @@  void multifd_load_cleanup(void)
 
         qemu_thread_join(&p->thread);
     }
+    dsa_cleanup();
     for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
@@ -1266,6 +1296,9 @@  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();
+    int ret;
+    Error *local_err = NULL;
 
     /*
      * Return successfully if multiFD recv state is already initialised
@@ -1275,6 +1308,15 @@  int multifd_load_setup(Error **errp)
         return 0;
     }
 
+    ret = dsa_init(dsa_parameter);
+    if (ret != 0) {
+        error_setg(&local_err, "multifd: Receiver failed to initialize DSA.");
+        error_propagate(errp, local_err);
+        return ret;
+    }
+
+    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);
@@ -1302,8 +1344,6 @@  int multifd_load_setup(Error **errp)
 
     for (i = 0; i < thread_count; i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
-        Error *local_err = NULL;
-        int ret;
 
         ret = multifd_recv_state->ops->recv_setup(p, &local_err);
         if (ret) {
@@ -1311,6 +1351,7 @@  int multifd_load_setup(Error **errp)
             return ret;
         }
     }
+
     return 0;
 }