Avoid unnecessary thread creation as no upcalls are generated,
resulting in idle threads waiting for process termination.
This optimization significantly reduces memory usage, cutting it
by half on a 128 CPU/thread system during testing, with the number
of threads reduced from 95 to 0.
Signed-off-by: Eelco Chaudron
---
v2: Sending this as a separate patch.
lib/dpif-netdev.c | 10 +-
ofproto/ofproto-dpif-upcall.c | 25 -
2 files changed, 25 insertions(+), 10 deletions(-)
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index c1981137f..1a29ab7ac 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -5250,6 +5250,14 @@ dpif_netdev_set_config(struct dpif *dpif, const struct
smap *other_config)
return 0;
}
+static bool
+dpif_netdev_number_handlers_required(struct dpif *dpif_ OVS_UNUSED,
+ uint32_t *n_handlers)
+{
+*n_handlers = 0;
+return true;
+}
+
/* Parses affinity list and returns result in 'core_ids'. */
static int
parse_affinity_list(const char *affinity_list, unsigned *core_ids, int n_rxq)
@@ -9985,7 +9993,7 @@ const struct dpif_class dpif_netdev_class = {
dpif_netdev_offload_stats_get,
NULL, /* recv_set */
NULL, /* handlers_set */
-NULL, /* number_handlers_required */
+dpif_netdev_number_handlers_required,
dpif_netdev_set_config,
dpif_netdev_queue_to_priority,
NULL, /* recv */
diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c
index b5cbeed87..9a5c5c29c 100644
--- a/ofproto/ofproto-dpif-upcall.c
+++ b/ofproto/ofproto-dpif-upcall.c
@@ -584,7 +584,7 @@ static void
udpif_start_threads(struct udpif *udpif, uint32_t n_handlers_,
uint32_t n_revalidators_)
{
-if (udpif && n_handlers_ && n_revalidators_) {
+if (udpif && n_revalidators_) {
/* Creating a thread can take a significant amount of time on some
* systems, even hundred of milliseconds, so quiesce around it. */
ovsrcu_quiesce_start();
@@ -592,14 +592,19 @@ udpif_start_threads(struct udpif *udpif, uint32_t
n_handlers_,
udpif->n_handlers = n_handlers_;
udpif->n_revalidators = n_revalidators_;
-udpif->handlers = xzalloc(udpif->n_handlers * sizeof *udpif->handlers);
-for (size_t i = 0; i < udpif->n_handlers; i++) {
-struct handler *handler = &udpif->handlers[i];
+if (udpif->n_handlers) {
+udpif->handlers = xzalloc(udpif->n_handlers
+ * sizeof *udpif->handlers);
+for (size_t i = 0; i < udpif->n_handlers; i++) {
+struct handler *handler = &udpif->handlers[i];
-handler->udpif = udpif;
-handler->handler_id = i;
-handler->thread = ovs_thread_create(
-"handler", udpif_upcall_handler, handler);
+handler->udpif = udpif;
+handler->handler_id = i;
+handler->thread = ovs_thread_create(
+"handler", udpif_upcall_handler, handler);
+}
+} else {
+udpif->handlers = NULL;
}
atomic_init(&udpif->enable_ufid, udpif->backer->rt_support.ufid);
@@ -662,7 +667,9 @@ udpif_set_threads(struct udpif *udpif, uint32_t n_handlers_,
if (dpif_number_handlers_required(udpif->dpif, &n_handlers_requested)) {
forced = true;
if (!n_revalidators_) {
-n_revalidators_requested = n_handlers_requested / 4 + 1;
+n_revalidators_requested = (n_handlers_requested
+? n_handlers_requested
+: MAX(count_cpu_cores(), 2)) / 4 + 1;
} else {
n_revalidators_requested = n_revalidators_;
}
--
2.43.0
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