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authorSirshak Das <sirshak.das@arm.com>2019-02-05 01:33:33 -0600
committerFlorin Coras <florin.coras@gmail.com>2019-04-16 19:33:21 +0000
commit28aa539f7da7b172d0f35ea9a63f3986939477f7 (patch)
treebe856eb44878b604b2fc93beffb7268db77b457b /src/vnet/session/session_node.c
parent39d04099467414175803273433c95a96c0276252 (diff)
svm_fifo rework to avoid contention on cursize
Problems Addressed: - Contention of cursize by producer and consumer. - Reduce the no of modulo operations. Changes: - Synchronization between producer and consumer changed from cursize to head and tail indexes Implications: reduces the usable size of fifo by 1. - Using weaker memory ordering C++11 atomics to access head and tail based on producer and consumer role. - Head and tail indexes are unsigned 32 bit integers. Additions and subtraction on them are implicit 32 bit Modulo operation. - Adding weaker memory ordering variants of max_enq, max_deq, is_empty and is_full Using them appropriately in all places. Perfomance improvement (iperf3 via Hoststack): iperf3 Server: Marvell ThunderX2(AArch64) - iperf3 Client: Skylake(x86) ~6%(256 rxd/txd) - ~11%(2048 rxd/txd) Change-Id: I1d484e000e437430fdd5a819657d1c6b62443018 Signed-off-by: Sirshak Das <sirshak.das@arm.com> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Diffstat (limited to 'src/vnet/session/session_node.c')
-rw-r--r--src/vnet/session/session_node.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index 2eac5152e16..c894c437cde 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -82,7 +82,8 @@ session_mq_accepted_reply_handler (void *data)
{
old_state = s->session_state;
s->session_state = SESSION_STATE_READY;
- if (!svm_fifo_is_empty (s->rx_fifo))
+
+ if (!svm_fifo_is_empty_prod (s->rx_fifo))
app_worker_lock_and_send_event (app_wrk, s, SESSION_IO_EVT_RX);
/* Closed while waiting for app to reply. Resend disconnect */
@@ -557,7 +558,7 @@ session_tx_set_dequeue_params (vlib_main_t * vm, session_tx_context_t * ctx,
u32 max_segs, u8 peek_data)
{
u32 n_bytes_per_buf, n_bytes_per_seg;
- ctx->max_dequeue = svm_fifo_max_dequeue (ctx->s->tx_fifo);
+ ctx->max_dequeue = svm_fifo_max_dequeue_cons (ctx->s->tx_fifo);
if (peek_data)
{
/* Offset in rx fifo from where to peek data */
@@ -788,7 +789,7 @@ session_tx_fifo_read_and_snd_i (vlib_main_t * vm, vlib_node_runtime_t * node,
svm_fifo_overwrite_head (ctx->s->tx_fifo, (u8 *) & ctx->hdr,
sizeof (session_dgram_pre_hdr_t));
/* More data needs to be read */
- else if (svm_fifo_max_dequeue (ctx->s->tx_fifo) > 0)
+ else if (svm_fifo_max_dequeue_cons (ctx->s->tx_fifo) > 0)
if (svm_fifo_set_event (ctx->s->tx_fifo))
vec_add1 (wrk->pending_event_vector, *e);
}
@@ -956,7 +957,8 @@ session_queue_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
* and the tx queue is still not empty, try to wait for some
* dispatch cycles */
if (!e->postponed
- || (e->postponed < 200 && svm_fifo_max_dequeue (s->tx_fifo)))
+ || (e->postponed < 200
+ && svm_fifo_max_dequeue_cons (s->tx_fifo)))
{
e->postponed += 1;
vec_add1 (wrk->pending_disconnects, *e);