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/application_interface.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'src/vnet/session/application_interface.h') diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h index 8323e72e768..b49744c0b29 100644 --- a/src/vnet/session/application_interface.h +++ b/src/vnet/session/application_interface.h @@ -459,7 +459,7 @@ app_send_dgram_raw (svm_fifo_t * f, app_session_transport_t * at, session_dgram_hdr_t hdr; int rv; - max_enqueue = svm_fifo_max_enqueue (f); + max_enqueue = svm_fifo_max_enqueue_prod (f); if (max_enqueue <= sizeof (session_dgram_hdr_t)) return 0; @@ -533,7 +533,7 @@ app_recv_dgram_raw (svm_fifo_t * f, u8 * buf, u32 len, u32 max_deq; int rv; - max_deq = svm_fifo_max_dequeue (f); + max_deq = svm_fifo_max_dequeue_cons (f); if (max_deq < sizeof (session_dgram_hdr_t)) { if (clear_evt) -- cgit 1.2.3-korg