From 978788903b54a9ecdab045c67f94c4ba79633a9f Mon Sep 17 00:00:00 2001 From: Steven Date: Tue, 29 Aug 2017 09:23:26 -0700 Subject: vhost: Cache qsz_mask instead of qsz in vhost_user_vring_t In the data path, we grab qsz from vhost_user_vring_t to compute qsz_mask and store it in a stack variable to use on many occasions. We never use qsz for any meaningful purpose. It is more useful to cache qsz_mask in vhost_user_vring_t to avoid the needless computation in the data path. Change-Id: Idf4d94a9754d5c75c899f1f4f59602275b9904a6 Signed-off-by: Steven --- src/vnet/devices/virtio/vhost-user.c | 58 +++++++++++++++++------------------- src/vnet/devices/virtio/vhost-user.h | 2 +- 2 files changed, 28 insertions(+), 32 deletions(-) (limited to 'src/vnet/devices') diff --git a/src/vnet/devices/virtio/vhost-user.c b/src/vnet/devices/virtio/vhost-user.c index 82f7653356d..bfd3e73e64a 100644 --- a/src/vnet/devices/virtio/vhost-user.c +++ b/src/vnet/devices/virtio/vhost-user.c @@ -854,7 +854,7 @@ vhost_user_socket_read (unix_file_t * uf) (msg.state.num == 0) || /* it cannot be zero */ ((msg.state.num - 1) & msg.state.num)) /* must be power of 2 */ goto close_socket; - vui->vrings[msg.state.index].qsz = msg.state.num; + vui->vrings[msg.state.index].qsz_mask = msg.state.num - 1; break; case VHOST_USER_SET_VRING_ADDR: @@ -1288,9 +1288,8 @@ vhost_user_rx_trace (vhost_trace_t * t, vlib_buffer_t * b, vhost_user_vring_t * txvq) { vhost_user_main_t *vum = &vhost_user_main; - u32 qsz_mask = txvq->qsz - 1; u32 last_avail_idx = txvq->last_avail_idx; - u32 desc_current = txvq->avail->ring[last_avail_idx & qsz_mask]; + u32 desc_current = txvq->avail->ring[last_avail_idx & txvq->qsz_mask]; vring_desc_t *hdr_desc = 0; virtio_net_hdr_mrg_rxbuf_t *hdr; u32 hint = 0; @@ -1409,19 +1408,19 @@ vhost_user_rx_discard_packet (vlib_main_t * vm, */ u32 discarded_packets = 0; u32 avail_idx = txvq->avail->idx; - u16 qsz_mask = txvq->qsz - 1; while (discarded_packets != discard_max) { if (avail_idx == txvq->last_avail_idx) goto out; u16 desc_chain_head = - txvq->avail->ring[txvq->last_avail_idx & qsz_mask]; + txvq->avail->ring[txvq->last_avail_idx & txvq->qsz_mask]; txvq->last_avail_idx++; - txvq->used->ring[txvq->last_used_idx & qsz_mask].id = desc_chain_head; - txvq->used->ring[txvq->last_used_idx & qsz_mask].len = 0; + txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].id = + desc_chain_head; + txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].len = 0; vhost_user_log_dirty_ring (vui, txvq, - ring[txvq->last_used_idx & qsz_mask]); + ring[txvq->last_used_idx & txvq->qsz_mask]); txvq->last_used_idx++; discarded_packets++; } @@ -1469,7 +1468,6 @@ vhost_user_if_input (vlib_main_t * vm, u32 n_left_to_next, *to_next; u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT; u32 n_trace = vlib_get_trace_count (vm, node); - u16 qsz_mask; u32 map_hint = 0; u16 thread_index = vlib_get_thread_index (); u16 copy_len = 0; @@ -1529,7 +1527,7 @@ vhost_user_if_input (vlib_main_t * vm, return 0; } - if (PREDICT_FALSE (n_left == txvq->qsz)) + if (PREDICT_FALSE (n_left == (txvq->qsz_mask + 1))) { /* * Informational error logging when VPP is not @@ -1539,8 +1537,6 @@ vhost_user_if_input (vlib_main_t * vm, VHOST_USER_INPUT_FUNC_ERROR_FULL_RX_QUEUE, 1); } - qsz_mask = txvq->qsz - 1; - if (n_left > VLIB_FRAME_SIZE) n_left = VLIB_FRAME_SIZE; @@ -1605,7 +1601,8 @@ vhost_user_if_input (vlib_main_t * vm, break; } - desc_current = txvq->avail->ring[txvq->last_avail_idx & qsz_mask]; + desc_current = + txvq->avail->ring[txvq->last_avail_idx & txvq->qsz_mask]; vum->cpus[thread_index].rx_buffers_len--; bi_current = (vum->cpus[thread_index].rx_buffers) [vum->cpus[thread_index].rx_buffers_len]; @@ -1621,10 +1618,12 @@ vhost_user_if_input (vlib_main_t * vm, rx_buffers_len - 1], LOAD); /* Just preset the used descriptor id and length for later */ - txvq->used->ring[txvq->last_used_idx & qsz_mask].id = desc_current; - txvq->used->ring[txvq->last_used_idx & qsz_mask].len = 0; + txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].id = + desc_current; + txvq->used->ring[txvq->last_used_idx & txvq->qsz_mask].len = 0; vhost_user_log_dirty_ring (vui, txvq, - ring[txvq->last_used_idx & qsz_mask]); + ring[txvq->last_used_idx & + txvq->qsz_mask]); /* The buffer should already be initialized */ b_head->total_length_not_including_first_buffer = 0; @@ -1889,9 +1888,8 @@ vhost_user_tx_trace (vhost_trace_t * t, vlib_buffer_t * b, vhost_user_vring_t * rxvq) { vhost_user_main_t *vum = &vhost_user_main; - u32 qsz_mask = rxvq->qsz - 1; u32 last_avail_idx = rxvq->last_avail_idx; - u32 desc_current = rxvq->avail->ring[last_avail_idx & qsz_mask]; + u32 desc_current = rxvq->avail->ring[last_avail_idx & rxvq->qsz_mask]; vring_desc_t *hdr_desc = 0; u32 hint = 0; @@ -1979,7 +1977,6 @@ vhost_user_tx (vlib_main_t * vm, pool_elt_at_index (vum->vhost_user_interfaces, rd->dev_instance); u32 qid = ~0; vhost_user_vring_t *rxvq; - u16 qsz_mask; u8 error; u32 thread_index = vlib_get_thread_index (); u32 map_hint = 0; @@ -2006,8 +2003,6 @@ vhost_user_tx (vlib_main_t * vm, if (PREDICT_FALSE (vui->use_tx_spinlock)) vhost_user_vring_lock (vui, qid); - qsz_mask = rxvq->qsz - 1; /* qsz is always power of 2 */ - retry: error = VHOST_USER_TX_FUNC_ERROR_NONE; tx_headers_len = 0; @@ -2043,7 +2038,7 @@ retry: desc_table = rxvq->desc; desc_head = desc_index = - rxvq->avail->ring[rxvq->last_avail_idx & qsz_mask]; + rxvq->avail->ring[rxvq->last_avail_idx & rxvq->qsz_mask]; /* Go deeper in case of indirect descriptor * I don't know of any driver providing indirect for RX. */ @@ -2108,13 +2103,13 @@ retry: &vum->cpus[thread_index].tx_headers[tx_headers_len - 1]; //Move from available to used buffer - rxvq->used->ring[rxvq->last_used_idx & qsz_mask].id = + rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].id = desc_head; - rxvq->used->ring[rxvq->last_used_idx & qsz_mask].len = + rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].len = desc_len; vhost_user_log_dirty_ring (vui, rxvq, ring[rxvq->last_used_idx & - qsz_mask]); + rxvq->qsz_mask]); rxvq->last_avail_idx++; rxvq->last_used_idx++; @@ -2133,7 +2128,7 @@ retry: desc_table = rxvq->desc; desc_head = desc_index = - rxvq->avail->ring[rxvq->last_avail_idx & qsz_mask]; + rxvq->avail->ring[rxvq->last_avail_idx & rxvq->qsz_mask]; if (PREDICT_FALSE (rxvq->desc[desc_head].flags & VIRTQ_DESC_F_INDIRECT)) { @@ -2201,10 +2196,10 @@ retry: } //Move from available to used ring - rxvq->used->ring[rxvq->last_used_idx & qsz_mask].id = desc_head; - rxvq->used->ring[rxvq->last_used_idx & qsz_mask].len = desc_len; + rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].id = desc_head; + rxvq->used->ring[rxvq->last_used_idx & rxvq->qsz_mask].len = desc_len; vhost_user_log_dirty_ring (vui, rxvq, - ring[rxvq->last_used_idx & qsz_mask]); + ring[rxvq->last_used_idx & rxvq->qsz_mask]); rxvq->last_avail_idx++; rxvq->last_used_idx++; @@ -3263,7 +3258,8 @@ show_vhost_user_command_fn (vlib_main_t * vm, vlib_cli_output (vm, " qsz %d last_avail_idx %d last_used_idx %d\n", - vui->vrings[q].qsz, vui->vrings[q].last_avail_idx, + vui->vrings[q].qsz_mask + 1, + vui->vrings[q].last_avail_idx, vui->vrings[q].last_used_idx); if (vui->vrings[q].avail && vui->vrings[q].used) @@ -3286,7 +3282,7 @@ show_vhost_user_command_fn (vlib_main_t * vm, " id addr len flags next user_addr\n"); vlib_cli_output (vm, " ===== ================== ===== ====== ===== ==================\n"); - for (j = 0; j < vui->vrings[q].qsz; j++) + for (j = 0; j < vui->vrings[q].qsz_mask + 1; j++) { u32 mem_hint = 0; vlib_cli_output (vm, diff --git a/src/vnet/devices/virtio/vhost-user.h b/src/vnet/devices/virtio/vhost-user.h index ed147a470d2..ad6c4219706 100644 --- a/src/vnet/devices/virtio/vhost-user.h +++ b/src/vnet/devices/virtio/vhost-user.h @@ -191,7 +191,7 @@ typedef struct vhost_user_msg { typedef struct { CLIB_CACHE_LINE_ALIGN_MARK (cacheline0); - u16 qsz; + u16 qsz_mask; u16 last_avail_idx; u16 last_used_idx; u16 n_since_last_int; -- cgit 1.2.3-korg