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/http_server.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'src/vnet/session-apps/http_server.c') diff --git a/src/vnet/session-apps/http_server.c b/src/vnet/session-apps/http_server.c index 4547a4dc4ef..c7e06bfbb2d 100644 --- a/src/vnet/session-apps/http_server.c +++ b/src/vnet/session-apps/http_server.c @@ -503,7 +503,7 @@ session_rx_request (http_session_t * hs) int n_read; cursize = vec_len (hs->rx_buf); - max_dequeue = svm_fifo_max_dequeue (hs->rx_fifo); + max_dequeue = svm_fifo_max_dequeue_cons (hs->rx_fifo); if (PREDICT_FALSE (max_dequeue == 0)) return -1; @@ -511,7 +511,7 @@ session_rx_request (http_session_t * hs) n_read = app_recv_stream_raw (hs->rx_fifo, hs->rx_buf + cursize, max_dequeue, 0, 0 /* peek */ ); ASSERT (n_read == max_dequeue); - if (svm_fifo_is_empty (hs->rx_fifo)) + if (svm_fifo_is_empty_cons (hs->rx_fifo)) svm_fifo_unset_event (hs->rx_fifo); _vec_len (hs->rx_buf) = cursize + n_read; -- cgit 1.2.3-korg