This allows us to control the algorithm used to spread traffic between
sockets, adding more fine grained control. If the user does not
specify a fanout mode, the PMD driver will default to
PACKET_FANOUT_HASH.
Signed-off-by: Tudor Cornea <tudor.cor...@gmail.com>
---
v3:
* Removed PACKET_FANOUT ifdef. The feature has existed since Linux 3.1
* Removed PACKET_FANOUT_FLAG_ROLLOVER ifdef
* Simplified the get_fanout() function
* Renamed mode variable to load_balance.
I was also thinking of load_balance_mode as an alternative.
* Removed space between get_fanout and following if statement
* Improved documentation. Added link to manual page for PACKET_FANOUT
v2:
* Renamed the patch
* Replaced packet_fanout argument with fanout_mode, which allows
more fine grained control
---
doc/guides/nics/af_packet.rst | 16 +++-
drivers/net/af_packet/rte_eth_af_packet.c | 89 ++++++++++++++++++-----
2 files changed, 84 insertions(+), 21 deletions(-)
diff --git a/doc/guides/nics/af_packet.rst b/doc/guides/nics/af_packet.rst
index a343d3a961..2ec9e9e674 100644
--- a/doc/guides/nics/af_packet.rst
+++ b/doc/guides/nics/af_packet.rst
@@ -13,8 +13,6 @@ PACKET_MMAP, which provides a mmapped ring buffer, shared
between user space
and kernel, that's used to send and receive packets. This helps reducing system
calls and the copies needed between user space and Kernel.
-The PACKET_FANOUT_HASH behavior of AF_PACKET is used for frame reception.
-
Options and inherent limitations
--------------------------------
@@ -25,11 +23,23 @@ Some of these, in turn, will be used to configure the
PACKET_MMAP settings.
* ``qpairs`` - number of Rx and Tx queues (optional, default 1);
* ``qdisc_bypass`` - set PACKET_QDISC_BYPASS option in AF_PACKET (optional,
disabled by default);
+* ``fanout_mode`` - set fanout algorithm.
+ Possible choices: hash, lb, cpu, rollover, rnd, qm (optional, default
hash);
* ``blocksz`` - PACKET_MMAP block size (optional, default 4096);
* ``framesz`` - PACKET_MMAP frame size (optional, default 2048B; Note:
multiple
of 16B);
* ``framecnt`` - PACKET_MMAP frame count (optional, default 512).
+For details regarding ``fanout_mode`` argument, you can consult the
+`PACKET_FANOUT documentation
<https://www.man7.org/linux/man-pages/man7/packet.7.html>`_.
+
+As an example, when ``fanout_mode=cpu`` is selected, the PACKET_FANOUT_CPU
+mode will be set on the sockets, so that on frame reception, the socket
+will be selected based on the CPU on which the packet arrived.
+
+Only one ``fanout_mode`` can be chosen. If left unspecified, the default is to
+use the PACKET_FANOUT_HASH behavior of AF_PACKET for frame reception.
+
Because this implementation is based on PACKET_MMAP, and PACKET_MMAP has its
own pre-requisites, it should be noted that the inner workings of PACKET_MMAP
should be carefully considered before modifying some of these options (namely,
@@ -64,7 +74,7 @@ framecnt=512):
.. code-block:: console
-
--vdev=eth_af_packet0,iface=tap0,blocksz=4096,framesz=2048,framecnt=512,qpairs=1,qdisc_bypass=0
+
--vdev=eth_af_packet0,iface=tap0,blocksz=4096,framesz=2048,framecnt=512,qpairs=1,qdisc_bypass=0,fanout_mode=hash
Features and Limitations
------------------------
diff --git a/drivers/net/af_packet/rte_eth_af_packet.c
b/drivers/net/af_packet/rte_eth_af_packet.c
index ceb8d9356a..9ca43fc54e 100644
--- a/drivers/net/af_packet/rte_eth_af_packet.c
+++ b/drivers/net/af_packet/rte_eth_af_packet.c
@@ -36,6 +36,7 @@
#define ETH_AF_PACKET_FRAMESIZE_ARG "framesz"
#define ETH_AF_PACKET_FRAMECOUNT_ARG "framecnt"
#define ETH_AF_PACKET_QDISC_BYPASS_ARG "qdisc_bypass"
+#define ETH_AF_PACKET_FANOUT_MODE_ARG "fanout_mode"
#define DFLT_FRAME_SIZE (1 << 11)
#define DFLT_FRAME_COUNT (1 << 9)
@@ -96,6 +97,7 @@ static const char *valid_arguments[] = {
ETH_AF_PACKET_FRAMESIZE_ARG,
ETH_AF_PACKET_FRAMECOUNT_ARG,
ETH_AF_PACKET_QDISC_BYPASS_ARG,
+ ETH_AF_PACKET_FANOUT_MODE_ARG,
NULL
};
@@ -700,6 +702,53 @@ open_packet_iface(const char *key __rte_unused,
return 0;
}
+#define PACKET_FANOUT_INVALID -1
+
+static int
+get_fanout_group_id(int if_index)
+{
+ return (getpid() ^ if_index) & 0xffff;
+}
+
+static int
+get_fanout_mode(const char *fanout_mode)
+{
+ int load_balance = PACKET_FANOUT_FLAG_DEFRAG |
+ PACKET_FANOUT_FLAG_ROLLOVER;
+
+ if (!fanout_mode) {
+ /* Default */
+ load_balance |= PACKET_FANOUT_HASH;
+ } else if (!strcmp(fanout_mode, "hash")) {
+ load_balance |= PACKET_FANOUT_HASH;
+ } else if (!strcmp(fanout_mode, "lb")) {
+ load_balance |= PACKET_FANOUT_LB;
+ } else if (!strcmp(fanout_mode, "cpu")) {
+ load_balance |= PACKET_FANOUT_CPU;
+ } else if (!strcmp(fanout_mode, "rollover")) {
+ load_balance |= PACKET_FANOUT_ROLLOVER;
+ } else if (!strcmp(fanout_mode, "rnd")) {
+ load_balance |= PACKET_FANOUT_RND;
+ } else if (!strcmp(fanout_mode, "qm")) {
+ load_balance |= PACKET_FANOUT_QM;
+ } else {
+ /* Invalid Fanout Mode */
+ load_balance = PACKET_FANOUT_INVALID;
+ }
+
+ return load_balance;
+}
+
+static int
+get_fanout(const char *fanout_mode, int if_index)
+{
+ int load_balance = get_fanout_mode(fanout_mode);
+ if (load_balance != PACKET_FANOUT_INVALID)
+ return get_fanout_group_id(if_index) | (load_balance << 16);
+ else
+ return PACKET_FANOUT_INVALID;
+}
+
static int
rte_pmd_init_internals(struct rte_vdev_device *dev,
const int sockfd,
@@ -709,6 +758,7 @@ rte_pmd_init_internals(struct rte_vdev_device *dev,
unsigned int framesize,
unsigned int framecnt,
unsigned int qdisc_bypass,
+ const char *fanout_mode,
struct pmd_internals **internals,
struct rte_eth_dev **eth_dev,
struct rte_kvargs *kvlist)
@@ -727,9 +777,7 @@ rte_pmd_init_internals(struct rte_vdev_device *dev,
int rc, tpver, discard;
int qsockfd = -1;
unsigned int i, q, rdsize;
-#if defined(PACKET_FANOUT)
int fanout_arg;
-#endif
for (k_idx = 0; k_idx < kvlist->count; k_idx++) {
pair = &kvlist->pairs[k_idx];
@@ -809,13 +857,11 @@ rte_pmd_init_internals(struct rte_vdev_device *dev,
sockaddr.sll_protocol = htons(ETH_P_ALL);
sockaddr.sll_ifindex = (*internals)->if_index;
-#if defined(PACKET_FANOUT)
- fanout_arg = (getpid() ^ (*internals)->if_index) & 0xffff;
- fanout_arg |= (PACKET_FANOUT_HASH | PACKET_FANOUT_FLAG_DEFRAG) << 16;
-#if defined(PACKET_FANOUT_FLAG_ROLLOVER)
- fanout_arg |= PACKET_FANOUT_FLAG_ROLLOVER << 16;
-#endif
-#endif
+ fanout_arg = get_fanout(fanout_mode, (*internals)->if_index);
+ if (fanout_arg == PACKET_FANOUT_INVALID) {
+ PMD_LOG(ERR, "Invalid fanout mode: %s", fanout_mode);
+ goto error;
+ }
for (q = 0; q < nb_queues; q++) {
/* Open an AF_PACKET socket for this queue... */
@@ -926,16 +972,17 @@ rte_pmd_init_internals(struct rte_vdev_device *dev,
goto error;
}
-#if defined(PACKET_FANOUT)
- rc = setsockopt(qsockfd, SOL_PACKET, PACKET_FANOUT,
- &fanout_arg, sizeof(fanout_arg));
- if (rc == -1) {
- PMD_LOG_ERRNO(ERR,
- "%s: could not set PACKET_FANOUT on AF_PACKET
socket for %s",
- name, pair->value);
- goto error;
+ if (nb_queues > 1) {
+ rc = setsockopt(qsockfd, SOL_PACKET, PACKET_FANOUT,
+ &fanout_arg, sizeof(fanout_arg));
+ if (rc == -1) {
+ PMD_LOG_ERRNO(ERR,
+ "%s: could not set PACKET_FANOUT "
+ "on AF_PACKET socket for %s",
+ name, pair->value);
+ goto error;
+ }
}
-#endif
}
/* reserve an ethdev entry */
@@ -1003,6 +1050,7 @@ rte_eth_from_packet(struct rte_vdev_device *dev,
unsigned int framecount = DFLT_FRAME_COUNT;
unsigned int qpairs = 1;
unsigned int qdisc_bypass = 1;
+ const char *fanout_mode = NULL;
/* do some parameter checking */
if (*sockfd < 0)
@@ -1065,6 +1113,10 @@ rte_eth_from_packet(struct rte_vdev_device *dev,
}
continue;
}
+ if (strstr(pair->key, ETH_AF_PACKET_FANOUT_MODE_ARG) != NULL) {
+ fanout_mode = pair->value;
+ continue;
+ }
}
if (framesize > blocksize) {
@@ -1091,6 +1143,7 @@ rte_eth_from_packet(struct rte_vdev_device *dev,
blocksize, blockcount,
framesize, framecount,
qdisc_bypass,
+ fanout_mode,
&internals, ð_dev,
kvlist) < 0)
return -1;
--
2.34.1
