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/tests/vnet/session/tcp_echo.c | 4 ++-- src/tests/vnet/session/udp_echo.c | 7 ++++--- 2 files changed, 6 insertions(+), 5 deletions(-) (limited to 'src/tests') diff --git a/src/tests/vnet/session/tcp_echo.c b/src/tests/vnet/session/tcp_echo.c index d76e9395a75..99b6765cdf5 100644 --- a/src/tests/vnet/session/tcp_echo.c +++ b/src/tests/vnet/session/tcp_echo.c @@ -507,7 +507,7 @@ recv_data_chunk (echo_main_t * em, echo_session_t * s, u8 * rx_buf) { int n_to_read, n_read; - n_to_read = svm_fifo_max_dequeue (s->rx_fifo); + n_to_read = svm_fifo_max_dequeue_cons (s->rx_fifo); if (!n_to_read) return; @@ -1063,7 +1063,7 @@ server_handle_rx (echo_main_t * em, session_event_t * e) * message queue */ svm_fifo_unset_event (s->rx_fifo); - max_dequeue = svm_fifo_max_dequeue (s->rx_fifo); + max_dequeue = svm_fifo_max_dequeue_cons (s->rx_fifo); if (PREDICT_FALSE (!max_dequeue)) return; diff --git a/src/tests/vnet/session/udp_echo.c b/src/tests/vnet/session/udp_echo.c index 4fd6c8635a8..91d5dccedcc 100644 --- a/src/tests/vnet/session/udp_echo.c +++ b/src/tests/vnet/session/udp_echo.c @@ -454,7 +454,7 @@ cut_through_thread_fn (void *arg) else { /* We don't do anything with the data, drop it */ - actual_transfer = svm_fifo_max_dequeue (rx_fifo); + actual_transfer = svm_fifo_max_dequeue_cons (rx_fifo); svm_fifo_dequeue_drop (rx_fifo, actual_transfer); } } @@ -724,7 +724,7 @@ send_test_chunk (udp_echo_main_t * utm, app_session_t * s, u32 bytes) test_buf_offset = utm->bytes_sent % test_buf_len; bytes_this_chunk = clib_min (test_buf_len - test_buf_offset, utm->bytes_to_send); - enq_space = svm_fifo_max_enqueue (s->tx_fifo); + enq_space = svm_fifo_max_enqueue_prod (s->tx_fifo); bytes_this_chunk = clib_min (bytes_this_chunk, enq_space); written = app_send (s, test_data + test_buf_offset, bytes_this_chunk, @@ -975,7 +975,8 @@ server_handle_fifo_event_rx (udp_echo_main_t * utm, u32 session_index) rx_fifo = session->rx_fifo; tx_fifo = session->tx_fifo; - max_dequeue = svm_fifo_max_dequeue (rx_fifo); + + max_dequeue = svm_fifo_max_dequeue_cons (rx_fifo); /* Allow enqueuing of a new event */ svm_fifo_unset_event (rx_fifo); -- cgit 1.2.3-korg