From 25f635852aee76255f7210c43d43668a80fdccce Mon Sep 17 00:00:00 2001
From: Damjan Marion <damarion@cisco.com>
Date: Mon, 6 Mar 2017 21:51:00 +0100
Subject: [PATCH] dpdk: dpdk-input optimizations and fixes
- fix issue caused by assumption that ethertype starts at 0
- intoduce buffer templates to speed-up vlib_buffer_t metadata
initialization
- avoid check for multiseg buffers inside loop if multiseg is disabled
- interleave prefetches to reduce load on L1 cache
Change-Id: I3b76e6d3e1e15ed28f01625edb7fbe9f38112e03
Signed-off-by: Damjan Marion <damarion@cisco.com>
---
src/plugins/dpdk.am | 4 +
src/plugins/dpdk/device/dpdk.h | 3 +
src/plugins/dpdk/device/init.c | 15 +++
src/plugins/dpdk/device/node.c | 200 +++++++++++++++++----------------
4 files changed, 126 insertions(+), 96 deletions(-)
diff --git a/src/plugins/dpdk.am b/src/plugins/dpdk.am
index 01383de60ae..f1a37ae2710 100644
--- a/src/plugins/dpdk.am
+++ b/src/plugins/dpdk.am
@@ -16,6 +16,10 @@ vppplugins_LTLIBRARIES += dpdk_plugin.la
dpdk_plugin_la_LDFLAGS = $(AM_LDFLAGS) -Wl,--whole-archive,-l:libdpdk.a,--no-whole-archive,-lm,-ldl
+# due to internal compiler error in GCC when compiling dpdk/device/node.c
+# debug sysmbols level reduced to 1. See GCC PR #79953 for details
+CFLAGS += -g1
+
dpdk_plugin_la_SOURCES = \
dpdk/main.c \
dpdk/buffer.c \
diff --git a/src/plugins/dpdk/device/dpdk.h b/src/plugins/dpdk/device/dpdk.h
index 092c7dca604..84f86ae28dd 100644
--- a/src/plugins/dpdk/device/dpdk.h
+++ b/src/plugins/dpdk/device/dpdk.h
@@ -338,6 +338,9 @@ typedef struct
/* per-thread recycle lists */
u32 **recycle;
+ /* per-thread buffer templates */
+ vlib_buffer_t *buffer_templates;
+
/* buffer flags template, configurable to enable/disable tcp / udp cksum */
u32 buffer_flags_template;
diff --git a/src/plugins/dpdk/device/init.c b/src/plugins/dpdk/device/init.c
index 85ecde25a23..110d74571b5 100755
--- a/src/plugins/dpdk/device/init.c
+++ b/src/plugins/dpdk/device/init.c
@@ -572,6 +572,21 @@ dpdk_lib_init (dpdk_main_t * dm)
dm->buffer_flags_template &= ~(IP_BUFFER_L4_CHECKSUM_CORRECT
| IP_BUFFER_L4_CHECKSUM_COMPUTED);
+ /* vlib_buffer_t template */
+ vec_validate_aligned (dm->buffer_templates, tm->n_vlib_mains - 1,
+ CLIB_CACHE_LINE_BYTES);
+ for (i = 0; i < tm->n_vlib_mains; i++)
+ {
+ vlib_buffer_free_list_t *fl;
+ vlib_buffer_t *bt = vec_elt_at_index (dm->buffer_templates, i);
+ fl = vlib_buffer_get_free_list (vm,
+ VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
+ vlib_buffer_init_for_free_list (bt, fl);
+ bt->flags = dm->buffer_flags_template;
+ bt->current_data = -RTE_PKTMBUF_HEADROOM;
+ vnet_buffer (bt)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+ }
+
for (i = 0; i < nports; i++)
{
u8 addr[6];
diff --git a/src/plugins/dpdk/device/node.c b/src/plugins/dpdk/device/node.c
index 2120069e6f0..e8d502ca692 100644
--- a/src/plugins/dpdk/device/node.c
+++ b/src/plugins/dpdk/device/node.c
@@ -37,21 +37,21 @@ static char *dpdk_error_strings[] = {
always_inline int
vlib_buffer_is_ip4 (vlib_buffer_t * b)
{
- ethernet_header_t *h = (ethernet_header_t *) b->data;
+ ethernet_header_t *h = (ethernet_header_t *) vlib_buffer_get_current (b);
return (h->type == clib_host_to_net_u16 (ETHERNET_TYPE_IP4));
}
always_inline int
vlib_buffer_is_ip6 (vlib_buffer_t * b)
{
- ethernet_header_t *h = (ethernet_header_t *) b->data;
+ ethernet_header_t *h = (ethernet_header_t *) vlib_buffer_get_current (b);
return (h->type == clib_host_to_net_u16 (ETHERNET_TYPE_IP6));
}
always_inline int
vlib_buffer_is_mpls (vlib_buffer_t * b)
{
- ethernet_header_t *h = (ethernet_header_t *) b->data;
+ ethernet_header_t *h = (ethernet_header_t *) vlib_buffer_get_current (b);
return (h->type == clib_host_to_net_u16 (ETHERNET_TYPE_MPLS_UNICAST));
}
@@ -217,10 +217,35 @@ dpdk_prefetch_buffer (struct rte_mbuf *mb)
}
static_always_inline void
-dpdk_prefetch_buffer_data (struct rte_mbuf *mb)
+dpdk_prefetch_ethertype (struct rte_mbuf *mb)
{
- vlib_buffer_t *b = vlib_buffer_from_rte_mbuf (mb);
- CLIB_PREFETCH (b->data, CLIB_CACHE_LINE_BYTES, STORE);
+ CLIB_PREFETCH (mb->buf_addr + mb->data_off +
+ STRUCT_OFFSET_OF (ethernet_header_t, type),
+ CLIB_CACHE_LINE_BYTES, LOAD);
+}
+
+
+/*
+ This function should fill 1st cacheline of vlib_buffer_t metadata with data
+ from buffer template. Instead of filling field by field, we construct
+ template and then use 128/256 bit vector instruction to copy data.
+ This code first loads whole cacheline into 4 128-bit registers (xmm)
+ or two 256 bit registers (ymm) and then stores data into all 4 buffers
+ efectively saving on register load operations.
+*/
+
+static_always_inline void
+dpdk_buffer_init_from_template (void *d0, void *d1, void *d2, void *d3,
+ void *s)
+{
+ int i;
+ for (i = 0; i < 2; i++)
+ {
+ *(u8x32 *) (((u8 *) d0) + i * 32) =
+ *(u8x32 *) (((u8 *) d1) + i * 32) =
+ *(u8x32 *) (((u8 *) d2) + i * 32) =
+ *(u8x32 *) (((u8 *) d3) + i * 32) = *(u8x32 *) (((u8 *) s) + i * 32);
+ }
}
/*
@@ -229,7 +254,8 @@ dpdk_prefetch_buffer_data (struct rte_mbuf *mb)
*/
static_always_inline u32
dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
- vlib_node_runtime_t * node, u32 cpu_index, u16 queue_id)
+ vlib_node_runtime_t * node, u32 cpu_index, u16 queue_id,
+ int maybe_multiseg)
{
u32 n_buffers;
u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
@@ -239,7 +265,7 @@ dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
uword n_rx_bytes = 0;
u32 n_trace, trace_cnt __attribute__ ((unused));
vlib_buffer_free_list_t *fl;
- u32 buffer_flags_template;
+ vlib_buffer_t *bt = vec_elt_at_index (dm->buffer_templates, cpu_index);
if ((xd->flags & DPDK_DEVICE_FLAG_ADMIN_UP) == 0)
return 0;
@@ -251,8 +277,6 @@ dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
return 0;
}
- buffer_flags_template = dm->buffer_flags_template;
-
vec_reset_length (xd->d_trace_buffers[cpu_index]);
trace_cnt = n_trace = vlib_get_trace_count (vm, node);
@@ -272,33 +296,44 @@ dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
fl = vlib_buffer_get_free_list (vm, VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
+ /* Update buffer template */
+ vnet_buffer (bt)->sw_if_index[VLIB_RX] = xd->vlib_sw_if_index;
+ bt->error = node->errors[DPDK_ERROR_NONE];
+
mb_index = 0;
while (n_buffers > 0)
{
vlib_buffer_t *b0, *b1, *b2, *b3;
- u32 bi0, next0, l3_offset0;
- u32 bi1, next1, l3_offset1;
- u32 bi2, next2, l3_offset2;
- u32 bi3, next3, l3_offset3;
+ u32 bi0, next0;
+ u32 bi1, next1;
+ u32 bi2, next2;
+ u32 bi3, next3;
u8 error0, error1, error2, error3;
u64 or_ol_flags;
vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
- while (n_buffers > 8 && n_left_to_next > 4)
+ while (n_buffers >= 12 && n_left_to_next >= 4)
{
- struct rte_mbuf *mb0 = xd->rx_vectors[queue_id][mb_index];
- struct rte_mbuf *mb1 = xd->rx_vectors[queue_id][mb_index + 1];
- struct rte_mbuf *mb2 = xd->rx_vectors[queue_id][mb_index + 2];
- struct rte_mbuf *mb3 = xd->rx_vectors[queue_id][mb_index + 3];
+ struct rte_mbuf *mb0, *mb1, *mb2, *mb3;
- dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 4]);
- dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 5]);
- dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 6]);
- dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 7]);
+ /* prefetches are interleaved with the rest of the code to reduce
+ pressure on L1 cache */
+ dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 8]);
+ dpdk_prefetch_ethertype (xd->rx_vectors[queue_id][mb_index + 4]);
- if (xd->flags & DPDK_DEVICE_FLAG_MAYBE_MULTISEG)
+ mb0 = xd->rx_vectors[queue_id][mb_index];
+ mb1 = xd->rx_vectors[queue_id][mb_index + 1];
+ mb2 = xd->rx_vectors[queue_id][mb_index + 2];
+ mb3 = xd->rx_vectors[queue_id][mb_index + 3];
+
+ ASSERT (mb0);
+ ASSERT (mb1);
+ ASSERT (mb2);
+ ASSERT (mb3);
+
+ if (maybe_multiseg)
{
if (PREDICT_FALSE (mb0->nb_segs > 1))
dpdk_prefetch_buffer (mb0->next);
@@ -310,22 +345,29 @@ dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
dpdk_prefetch_buffer (mb3->next);
}
- ASSERT (mb0);
- ASSERT (mb1);
- ASSERT (mb2);
- ASSERT (mb3);
-
- or_ol_flags = (mb0->ol_flags | mb1->ol_flags |
- mb2->ol_flags | mb3->ol_flags);
b0 = vlib_buffer_from_rte_mbuf (mb0);
b1 = vlib_buffer_from_rte_mbuf (mb1);
b2 = vlib_buffer_from_rte_mbuf (mb2);
b3 = vlib_buffer_from_rte_mbuf (mb3);
- vlib_buffer_init_for_free_list (b0, fl);
- vlib_buffer_init_for_free_list (b1, fl);
- vlib_buffer_init_for_free_list (b2, fl);
- vlib_buffer_init_for_free_list (b3, fl);
+ dpdk_buffer_init_from_template (b0, b1, b2, b3, bt);
+
+ dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 9]);
+ dpdk_prefetch_ethertype (xd->rx_vectors[queue_id][mb_index + 5]);
+
+ /* current_data must be set to -RTE_PKTMBUF_HEADROOM in template */
+ b0->current_data += mb0->data_off;
+ b1->current_data += mb1->data_off;
+ b2->current_data += mb2->data_off;
+ b3->current_data += mb3->data_off;
+
+ b0->current_length = mb0->data_len;
+ b1->current_length = mb1->data_len;
+ b2->current_length = mb2->data_len;
+ b3->current_length = mb3->data_len;
+
+ dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 10]);
+ dpdk_prefetch_ethertype (xd->rx_vectors[queue_id][mb_index + 7]);
bi0 = vlib_get_buffer_index (vm, b0);
bi1 = vlib_get_buffer_index (vm, b1);
@@ -345,21 +387,17 @@ dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
}
else
{
- /* prefetch packet data for faster access to the ethertype */
- dpdk_prefetch_buffer_data (xd->rx_vectors[queue_id]
- [mb_index + 4]);
- dpdk_prefetch_buffer_data (xd->rx_vectors[queue_id]
- [mb_index + 5]);
- dpdk_prefetch_buffer_data (xd->rx_vectors[queue_id]
- [mb_index + 6]);
- dpdk_prefetch_buffer_data (xd->rx_vectors[queue_id]
- [mb_index + 7]);
next0 = dpdk_rx_next_from_etype (mb0, b0);
next1 = dpdk_rx_next_from_etype (mb1, b1);
next2 = dpdk_rx_next_from_etype (mb2, b2);
next3 = dpdk_rx_next_from_etype (mb3, b3);
}
+ dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 11]);
+ dpdk_prefetch_ethertype (xd->rx_vectors[queue_id][mb_index + 6]);
+
+ or_ol_flags = (mb0->ol_flags | mb1->ol_flags |
+ mb2->ol_flags | mb3->ol_flags);
if (PREDICT_FALSE (or_ol_flags & PKT_RX_IP_CKSUM_BAD))
{
dpdk_rx_error_from_mb (mb0, &next0, &error0);
@@ -371,46 +409,11 @@ dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
b2->error = node->errors[error2];
b3->error = node->errors[error3];
}
- else
- {
- b0->error = b1->error = node->errors[DPDK_ERROR_NONE];
- b2->error = b3->error = node->errors[DPDK_ERROR_NONE];
- }
- l3_offset0 = device_input_next_node_advance[next0];
- l3_offset1 = device_input_next_node_advance[next1];
- l3_offset2 = device_input_next_node_advance[next2];
- l3_offset3 = device_input_next_node_advance[next3];
-
- b0->current_data = l3_offset0 + mb0->data_off;
- b1->current_data = l3_offset1 + mb1->data_off;
- b2->current_data = l3_offset2 + mb2->data_off;
- b3->current_data = l3_offset3 + mb3->data_off;
-
- b0->current_data -= RTE_PKTMBUF_HEADROOM;
- b1->current_data -= RTE_PKTMBUF_HEADROOM;
- b2->current_data -= RTE_PKTMBUF_HEADROOM;
- b3->current_data -= RTE_PKTMBUF_HEADROOM;
-
- b0->current_length = mb0->data_len - l3_offset0;
- b1->current_length = mb1->data_len - l3_offset1;
- b2->current_length = mb2->data_len - l3_offset2;
- b3->current_length = mb3->data_len - l3_offset3;
-
- b0->flags = buffer_flags_template;
- b1->flags = buffer_flags_template;
- b2->flags = buffer_flags_template;
- b3->flags = buffer_flags_template;
-
- vnet_buffer (b0)->sw_if_index[VLIB_RX] = xd->vlib_sw_if_index;
- vnet_buffer (b1)->sw_if_index[VLIB_RX] = xd->vlib_sw_if_index;
- vnet_buffer (b2)->sw_if_index[VLIB_RX] = xd->vlib_sw_if_index;
- vnet_buffer (b3)->sw_if_index[VLIB_RX] = xd->vlib_sw_if_index;
-
- vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
- vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
- vnet_buffer (b2)->sw_if_index[VLIB_TX] = (u32) ~ 0;
- vnet_buffer (b3)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+ vlib_buffer_advance (b0, device_input_next_node_advance[next0]);
+ vlib_buffer_advance (b1, device_input_next_node_advance[next1]);
+ vlib_buffer_advance (b2, device_input_next_node_advance[next2]);
+ vlib_buffer_advance (b3, device_input_next_node_advance[next3]);
n_rx_bytes += mb0->pkt_len;
n_rx_bytes += mb1->pkt_len;
@@ -418,7 +421,7 @@ dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
n_rx_bytes += mb3->pkt_len;
/* Process subsequent segments of multi-segment packets */
- if (xd->flags & DPDK_DEVICE_FLAG_MAYBE_MULTISEG)
+ if (maybe_multiseg)
{
dpdk_process_subseq_segs (vm, b0, mb0, fl);
dpdk_process_subseq_segs (vm, b1, mb1, fl);
@@ -452,6 +455,13 @@ dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
{
struct rte_mbuf *mb0 = xd->rx_vectors[queue_id][mb_index];
+ if (PREDICT_TRUE (n_buffers > 3))
+ {
+ dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 2]);
+ dpdk_prefetch_ethertype (xd->rx_vectors[queue_id]
+ [mb_index + 1]);
+ }
+
ASSERT (mb0);
b0 = vlib_buffer_from_rte_mbuf (mb0);
@@ -460,7 +470,11 @@ dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
if (PREDICT_FALSE (mb0->nb_segs > 1))
dpdk_prefetch_buffer (mb0->next);
- vlib_buffer_init_for_free_list (b0, fl);
+ clib_memcpy (b0, bt, CLIB_CACHE_LINE_BYTES);
+
+ ASSERT (b0->current_data == -RTE_PKTMBUF_HEADROOM);
+ b0->current_data += mb0->data_off;
+ b0->current_length = mb0->data_len;
bi0 = vlib_get_buffer_index (vm, b0);
@@ -474,18 +488,9 @@ dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
next0 = dpdk_rx_next_from_etype (mb0, b0);
dpdk_rx_error_from_mb (mb0, &next0, &error0);
- b0->error = node->errors[error0];
- l3_offset0 = device_input_next_node_advance[next0];
+ vlib_buffer_advance (b0, device_input_next_node_advance[next0]);
- b0->current_data = l3_offset0;
- b0->current_data += mb0->data_off - RTE_PKTMBUF_HEADROOM;
- b0->current_length = mb0->data_len - l3_offset0;
-
- b0->flags = buffer_flags_template;
-
- vnet_buffer (b0)->sw_if_index[VLIB_RX] = xd->vlib_sw_if_index;
- vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
n_rx_bytes += mb0->pkt_len;
/* Process subsequent segments of multi-segment packets */
@@ -604,7 +609,10 @@ dpdk_input (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * f)
vec_foreach (dq, dm->devices_by_cpu[cpu_index])
{
xd = vec_elt_at_index(dm->devices, dq->device);
- n_rx_packets += dpdk_device_input (dm, xd, node, cpu_index, dq->queue_id);
+ if (xd->flags & DPDK_DEVICE_FLAG_MAYBE_MULTISEG)
+ n_rx_packets += dpdk_device_input (dm, xd, node, cpu_index, dq->queue_id, /* maybe_multiseg */ 1);
+ else
+ n_rx_packets += dpdk_device_input (dm, xd, node, cpu_index, dq->queue_id, /* maybe_multiseg */ 0);
}
/* *INDENT-ON* */