[PATCH v2 3/4] rsockets: distribute completion queue vectors among multiple cores

[Sreedhar Kodali <srkodali-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>]

 From: Sreedhar Kodali <srkodali-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>

     Distribute interrupt vectors among multiple cores while processing
     completion events.  By default the existing mechanism always
     defaults to core 0 for comp vector processing during the creation
     of a completion queue.  If the workload is very high, then this
     results in bottleneck at core 0 because the same core is used for
     both event and task processing.

     A '/comp_vector' option is exposed, the value of which is a range
     or comma separated list of cores for distributing interrupt
     vectors.  If not set, the existing mechanism prevails where in
     comp vector processing is directed to core 0.

     Signed-off-by: Sreedhar Kodali <srkodali-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
     ---

diff --git a/src/rsocket.c b/src/rsocket.c
index b70d56a..ffea0ca 100644
--- a/src/rsocket.c
+++ b/src/rsocket.c
@@ -116,6 +116,8 @@ static uint32_t def_mem = (1 << 17);
  static uint32_t def_wmem = (1 << 17);
  static uint32_t polling_time = 10;
  static uint16_t restart_onintr = 0;
+static uint16_t next_comp_vector = 0;
+static uint64_t comp_vector_mask = 0;

  /*
   * Immediate data format is determined by the upper bits
@@ -548,6 +550,37 @@ void rs_configure(void)
  		(void) fscanf(f, "%hu", &restart_onintr);
  		fclose(f);
  	}
+
+	if ((f = fopen(RS_CONF_DIR "/comp_vector", "r"))) {
+		char vbuf[256];
+		char *vptr;
+		vptr = fgets(vbuf, sizeof(vbuf), f);
+		fclose(f);
+		if (vptr) {
+			char *tok, *save, *tmp, *str, *tok2;
+			int lvect, uvect, vect;
+
+			for (str = vptr; ; str = NULL) {
+				tok = strtok_r(str, ",", &save);
+				if (tok == NULL) {
+					break;
+				}
+				if (!(tmp = strpbrk(tok, "-"))) {
+					lvect = uvect = atoi(tok);
+				} else {
+					tok2 = tmp + 1;
+					*tmp = '\0';
+					lvect = atoi(tok);
+					uvect = atoi(tok2);
+				}
+				lvect = (lvect < 0) ? 0 : ((lvect > 63) ? 63 : lvect);
+				uvect = (uvect < 0) ? 0 : ((uvect > 63) ? 63 : uvect);
+				for (vect = lvect; vect <= uvect; vect++) {
+					comp_vector_mask |= ((uint64_t)1 << vect);
+				}
+			}
+		}
+	}
  	init = 1;
  out:
  	pthread_mutex_unlock(&mut);
@@ -762,12 +795,27 @@ static int ds_init_bufs(struct ds_qp *qp)
   */
  static int rs_create_cq(struct rsocket *rs, struct rdma_cm_id *cm_id)
  {
+	int vector = 0;
+
  	cm_id->recv_cq_channel = ibv_create_comp_channel(cm_id->verbs);
  	if (!cm_id->recv_cq_channel)
  		return -1;

+	if (comp_vector_mask) {
+		int found = 0;
+		while (found == 0) {
+			if (comp_vector_mask & ((uint64_t) 1 << next_comp_vector)) {
+				found = 1;
+				vector = next_comp_vector;
+			}
+			if (++next_comp_vector == 64) {
+				next_comp_vector = 0;
+			}
+		}
+	}
+
  	cm_id->recv_cq = ibv_create_cq(cm_id->verbs, rs->sq_size + 
rs->rq_size,
-				       cm_id, cm_id->recv_cq_channel, 0);
+				       cm_id, cm_id->recv_cq_channel, vector);
  	if (!cm_id->recv_cq)
  		goto err1;


--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html