From 28aa539f7da7b172d0f35ea9a63f3986939477f7 Mon Sep 17 00:00:00 2001 From: Sirshak Das Date: Tue, 5 Feb 2019 01:33:33 -0600 Subject: 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 Reviewed-by: Honnappa Nagarahalli --- src/vnet/session-apps/echo_server.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'src/vnet/session-apps/echo_server.c') diff --git a/src/vnet/session-apps/echo_server.c b/src/vnet/session-apps/echo_server.c index d165fb35e01..4249ed83292 100644 --- a/src/vnet/session-apps/echo_server.c +++ b/src/vnet/session-apps/echo_server.c @@ -139,7 +139,7 @@ int echo_server_builtin_server_rx_callback_no_echo (session_t * s) { svm_fifo_t *rx_fifo = s->rx_fifo; - svm_fifo_dequeue_drop (rx_fifo, svm_fifo_max_dequeue (rx_fifo)); + svm_fifo_dequeue_drop (rx_fifo, svm_fifo_max_dequeue_cons (rx_fifo)); return 0; } @@ -161,10 +161,10 @@ echo_server_rx_callback (session_t * s) ASSERT (rx_fifo->master_thread_index == thread_index); ASSERT (tx_fifo->master_thread_index == thread_index); - max_enqueue = svm_fifo_max_enqueue (tx_fifo); + max_enqueue = svm_fifo_max_enqueue_prod (tx_fifo); if (!esm->is_dgram) { - max_dequeue = svm_fifo_max_dequeue (rx_fifo); + max_dequeue = svm_fifo_max_dequeue_cons (rx_fifo); } else { @@ -255,7 +255,7 @@ echo_server_rx_callback (session_t * s) if (n_written != max_transfer) clib_warning ("short trout! written %u read %u", n_written, max_transfer); - if (PREDICT_FALSE (svm_fifo_max_dequeue (rx_fifo))) + if (PREDICT_FALSE (svm_fifo_max_dequeue_cons (rx_fifo))) goto rx_event; return 0; -- cgit 1.2.3-korg