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/vcl/vcl_private.c | 10 +++++----- src/vcl/vppcom.c | 17 +++++++++-------- 2 files changed, 14 insertions(+), 13 deletions(-) (limited to 'src/vcl') diff --git a/src/vcl/vcl_private.c b/src/vcl/vcl_private.c index a572fd4d540..3e82becfc93 100644 --- a/src/vcl/vcl_private.c +++ b/src/vcl/vcl_private.c @@ -346,9 +346,9 @@ vcl_session_read_ready (vcl_session_t * session) return clib_fifo_elts (session->accept_evts_fifo); if (vcl_session_is_ct (session)) - return svm_fifo_max_dequeue (session->ct_rx_fifo); + return svm_fifo_max_dequeue_cons (session->ct_rx_fifo); - return svm_fifo_max_dequeue (session->rx_fifo); + return svm_fifo_max_dequeue_cons (session->rx_fifo); } int @@ -365,7 +365,7 @@ vcl_session_write_ready (vcl_session_t * session) if (PREDICT_FALSE (session->session_state & STATE_LISTEN)) { if (session->tx_fifo) - return svm_fifo_max_enqueue (session->tx_fifo); + return svm_fifo_max_enqueue_prod (session->tx_fifo); else return VPPCOM_EBADFD; } @@ -383,9 +383,9 @@ vcl_session_write_ready (vcl_session_t * session) } if (vcl_session_is_ct (session)) - return svm_fifo_max_enqueue (session->ct_tx_fifo); + return svm_fifo_max_enqueue_prod (session->ct_tx_fifo); - return svm_fifo_max_enqueue (session->tx_fifo); + return svm_fifo_max_enqueue_prod (session->tx_fifo); } /* diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c index 037df995510..b5953872f81 100644 --- a/src/vcl/vppcom.c +++ b/src/vcl/vppcom.c @@ -1496,14 +1496,14 @@ vppcom_session_read_internal (uint32_t session_handle, void *buf, int n, rx_fifo = is_ct ? s->ct_rx_fifo : s->rx_fifo; s->has_rx_evt = 0; - if (svm_fifo_is_empty (rx_fifo)) + if (svm_fifo_is_empty_cons (rx_fifo)) { if (is_nonblocking) { svm_fifo_unset_event (s->rx_fifo); return VPPCOM_EWOULDBLOCK; } - while (svm_fifo_is_empty (rx_fifo)) + while (svm_fifo_is_empty_cons (rx_fifo)) { if (vcl_session_is_closing (s)) return vcl_session_closing_error (s); @@ -1527,7 +1527,7 @@ vppcom_session_read_internal (uint32_t session_handle, void *buf, int n, else n_read = app_recv_stream_raw (rx_fifo, buf, n, 0, peek); - if (svm_fifo_is_empty (rx_fifo)) + if (svm_fifo_is_empty_cons (rx_fifo)) svm_fifo_unset_event (s->rx_fifo); VDBG (2, "session %u[0x%llx]: read %d bytes from (%p)", s->session_index, @@ -1577,14 +1577,14 @@ vppcom_session_read_segments (uint32_t session_handle, if (is_ct) svm_fifo_unset_event (s->rx_fifo); - if (svm_fifo_is_empty (rx_fifo)) + if (svm_fifo_is_empty_cons (rx_fifo)) { if (is_nonblocking) { svm_fifo_unset_event (rx_fifo); return VPPCOM_EWOULDBLOCK; } - while (svm_fifo_is_empty (rx_fifo)) + while (svm_fifo_is_empty_cons (rx_fifo)) { if (vcl_session_is_closing (s)) return vcl_session_closing_error (s); @@ -1681,14 +1681,15 @@ vppcom_session_write_inline (uint32_t session_handle, void *buf, size_t n, is_ct = vcl_session_is_ct (s); tx_fifo = is_ct ? s->ct_tx_fifo : s->tx_fifo; is_nonblocking = VCL_SESS_ATTR_TEST (s->attr, VCL_SESS_ATTR_NONBLOCK); + mq = wrk->app_event_queue; - if (svm_fifo_is_full (tx_fifo)) + if (svm_fifo_is_full_prod (tx_fifo)) { if (is_nonblocking) { return VPPCOM_EWOULDBLOCK; } - while (svm_fifo_is_full (tx_fifo)) + while (svm_fifo_is_full_prod (tx_fifo)) { svm_fifo_add_want_tx_ntf (tx_fifo, SVM_FIFO_WANT_TX_NOTIF); if (vcl_session_is_closing (s)) @@ -2003,7 +2004,7 @@ vppcom_select (int n_bits, vcl_si_set * read_map, vcl_si_set * write_map, continue; } - rv = svm_fifo_is_full (session->tx_fifo); + rv = svm_fifo_is_full_prod (session->tx_fifo); if (!rv) { clib_bitmap_set_no_check ((uword*)write_map, sid, 1); -- cgit 1.2.3-korg