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/udp/udp_input.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'src/vnet/udp/udp_input.c') diff --git a/src/vnet/udp/udp_input.c b/src/vnet/udp/udp_input.c index db634cb2ddb..52c29d7ebfa 100644 --- a/src/vnet/udp/udp_input.c +++ b/src/vnet/udp/udp_input.c @@ -229,7 +229,7 @@ udp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node, if (!uc0->is_connected) { - if (svm_fifo_max_enqueue (s0->rx_fifo) + if (svm_fifo_max_enqueue_prod (s0->rx_fifo) < b0->current_length + sizeof (session_dgram_hdr_t)) { error0 = UDP_ERROR_FIFO_FULL; @@ -255,7 +255,8 @@ udp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node, } else { - if (svm_fifo_max_enqueue (s0->rx_fifo) < b0->current_length) + if (svm_fifo_max_enqueue_prod (s0->rx_fifo) < + b0->current_length) { error0 = UDP_ERROR_FIFO_FULL; goto trace0; -- cgit 1.2.3-korg