1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
/*
*------------------------------------------------------------------
* Copyright (c) 2021 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*------------------------------------------------------------------
*/
#include <vlib/vlib.h>
#include <vnet/gso/gro_func.h>
#include <vnet/interface/tx_queue_funcs.h>
#include <vnet/devices/virtio/virtio.h>
#include <vnet/devices/virtio/virtio_inline.h>
static_always_inline uword
virtio_pre_input_inline (vlib_main_t *vm, virtio_vring_t *txq_vring,
vnet_hw_if_tx_queue_t *txq, u8 packet_coalesce,
u8 packet_buffering)
{
if (txq->shared_queue)
{
if (clib_spinlock_trylock (&txq_vring->lockp))
{
if (virtio_txq_is_scheduled (txq_vring))
return 0;
if (packet_coalesce)
vnet_gro_flow_table_schedule_node_on_dispatcher (
vm, txq, txq_vring->flow_table);
else if (packet_buffering)
virtio_vring_buffering_schedule_node_on_dispatcher (
vm, txq, txq_vring->buffering);
virtio_txq_set_scheduled (txq_vring);
clib_spinlock_unlock (&txq_vring->lockp);
}
}
else
{
if (packet_coalesce)
vnet_gro_flow_table_schedule_node_on_dispatcher (
vm, txq, txq_vring->flow_table);
else if (packet_buffering)
virtio_vring_buffering_schedule_node_on_dispatcher (
vm, txq, txq_vring->buffering);
}
return 0;
}
static uword
virtio_pre_input (vlib_main_t *vm, vlib_node_runtime_t *node,
vlib_frame_t *frame)
{
virtio_main_t *vim = &virtio_main;
vnet_main_t *vnm = vnet_get_main ();
virtio_if_t *vif;
pool_foreach (vif, vim->interfaces)
{
if (vif->packet_coalesce || vif->packet_buffering)
{
virtio_vring_t *txq_vring;
vec_foreach (txq_vring, vif->txq_vrings)
{
vnet_hw_if_tx_queue_t *txq =
vnet_hw_if_get_tx_queue (vnm, txq_vring->queue_index);
if (clib_bitmap_get (txq->threads, vm->thread_index) == 1)
virtio_pre_input_inline (vm, txq_vring, txq,
vif->packet_coalesce,
vif->packet_buffering);
}
}
}
return 0;
}
/**
* virtio interfaces support packet coalescing and buffering which
* depends on timer expiry to flush the stored packets periodically.
* Previously, virtio input node checked timer expiry and scheduled
* tx queue accordingly.
*
* In poll mode, timer expiry was handled naturally, as input node
* runs periodically. In interrupt mode, virtio input node was dependent
* on the interrupts send from backend. Stored packets could starve,
* if there would not be interrupts to input node.
*
* This problem had been solved through a dedicated process node which
* periodically sends interrupt to virtio input node given coalescing
* or buffering feature were enabled on an interface.
*
* But that approach worked with following limitations:
* 1) Each VPP thread should have (atleast) 1 rx queue of an interface
* (with buffering enabled). And rxqs and txqs should be placed on the
* same thread.
*
* New design provides solution to above problem(s) without any limitation
* through (dedicated) pre-input node running on each VPP thread when
* atleast 1 virtio interface is enabled with coalescing or buffering.
*/
VLIB_REGISTER_NODE (virtio_pre_input_node) = {
.function = virtio_pre_input,
.type = VLIB_NODE_TYPE_PRE_INPUT,
.name = "virtio-pre-input",
.state = VLIB_NODE_STATE_DISABLED,
};
void
virtio_pre_input_node_enable (vlib_main_t *vm, virtio_if_t *vif)
{
virtio_main_t *vim = &virtio_main;
if (vif->packet_coalesce || vif->packet_buffering)
{
vim->gro_or_buffering_if_count++;
if (vim->gro_or_buffering_if_count == 1)
{
foreach_vlib_main ()
{
vlib_node_set_state (this_vlib_main, virtio_pre_input_node.index,
VLIB_NODE_STATE_POLLING);
}
}
}
}
void
virtio_pre_input_node_disable (vlib_main_t *vm, virtio_if_t *vif)
{
virtio_main_t *vim = &virtio_main;
if (vif->packet_coalesce || vif->packet_buffering)
{
if (vim->gro_or_buffering_if_count > 0)
vim->gro_or_buffering_if_count--;
if (vim->gro_or_buffering_if_count == 0)
{
foreach_vlib_main ()
{
vlib_node_set_state (this_vlib_main, virtio_pre_input_node.index,
VLIB_NODE_STATE_DISABLED);
}
}
}
}
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
|
