* [RFC 2/2] examples: use optimal burst size
2025-11-26 8:24 [RFC 1/2] config: add optimal burst size configuration pbhagavatula
@ 2025-11-26 8:24 ` pbhagavatula
2025-11-26 9:57 ` [RFC 1/2] config: add optimal burst size configuration Morten Brørup
1 sibling, 0 replies; 5+ messages in thread
From: pbhagavatula @ 2025-11-26 8:24 UTC (permalink / raw)
To: mb, jerinj, Wisam Jaddo, Aman Singh, Chas Williams,
Min Hu (Connor),
Akhil Goyal, Anoob Joseph, Nicolas Chautru, David Hunt,
Chengwen Feng, Kevin Laatz, Bruce Richardson, Konstantin Ananyev,
Radu Nicolau, Tomasz Kantecki, Fan Zhang, Sunil Kumar Kori,
Pavan Nikhilesh, Anatoly Burakov, Sivaprasad Tummala,
Jingjing Wu, Volodymyr Fialko, Cristian Dumitrescu,
John McNamara, Maxime Coquelin, Chenbo Xia
Cc: dev
From: Pavan Nikhilesh <pbhagavatula@marvell.com>
Replace hardcoded burst sizes with RTE_OPTIMAL_BURST_SIZE to
adapt to platform capabilities.
Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
---
app/test-eventdev/evt_options.c | 2 +-
app/test-flow-perf/main.c | 2 +-
app/test-pmd/testpmd.h | 2 +-
app/test/test_link_bonding.c | 2 +-
app/test/test_link_bonding_mode4.c | 4 +--
app/test/test_pmd_perf.c | 2 +-
app/test/test_security_inline_proto.c | 2 +-
examples/bbdev_app/main.c | 2 +-
examples/bond/main.c | 2 +-
examples/distributor/main.c | 4 +--
examples/dma/dmafwd.c | 2 +-
examples/ethtool/ethtool-app/main.c | 2 +-
examples/ip_fragmentation/main.c | 2 +-
examples/ip_reassembly/main.c | 3 +--
examples/ipsec-secgw/ipsec-secgw.h | 4 +--
examples/ipv4_multicast/main.c | 2 +-
examples/l2fwd-cat/l2fwd-cat.c | 2 +-
examples/l2fwd-crypto/main.c | 2 +-
examples/l2fwd-event/l2fwd_common.h | 2 +-
examples/l2fwd-jobstats/main.c | 2 +-
examples/l2fwd-keepalive/main.c | 2 +-
examples/l2fwd-macsec/main.c | 2 +-
examples/l2fwd/main.c | 2 +-
examples/l3fwd-power/main.c | 2 +-
examples/l3fwd/l3fwd.h | 4 +--
examples/l3fwd/main.c | 29 +++++++++++++++-------
examples/link_status_interrupt/main.c | 4 +--
examples/multi_process/symmetric_mp/main.c | 2 +-
examples/ntb/ntb_fwd.c | 4 +--
examples/packet_ordering/main.c | 2 +-
examples/qos_meter/main.c | 4 +--
examples/qos_sched/main.h | 4 +--
examples/rxtx_callbacks/main.c | 2 +-
examples/skeleton/basicfwd.c | 2 +-
examples/vhost/main.h | 2 +-
examples/vhost_crypto/main.c | 2 +-
examples/vm_power_manager/main.c | 2 +-
examples/vmdq/main.c | 2 +-
examples/vmdq_dcb/main.c | 2 +-
39 files changed, 66 insertions(+), 56 deletions(-)
diff --git a/app/test-eventdev/evt_options.c b/app/test-eventdev/evt_options.c
index 0e70c971eb2e..55e2b07157d7 100644
--- a/app/test-eventdev/evt_options.c
+++ b/app/test-eventdev/evt_options.c
@@ -37,7 +37,7 @@ evt_options_default(struct evt_options *opt)
opt->expiry_nsec = 1E4; /* 10000ns ~10us */
opt->prod_type = EVT_PROD_TYPE_SYNT;
opt->eth_queues = 1;
- opt->vector_size = 64;
+ opt->vector_size = RTE_OPTIMAL_BURST_SIZE;
opt->vector_tmo_nsec = 100E3;
opt->crypto_op_type = RTE_CRYPTO_OP_TYPE_SYMMETRIC;
opt->crypto_cipher_alg = RTE_CRYPTO_CIPHER_NULL;
diff --git a/app/test-flow-perf/main.c b/app/test-flow-perf/main.c
index a8876acf1f90..13c5d6bf02eb 100644
--- a/app/test-flow-perf/main.c
+++ b/app/test-flow-perf/main.c
@@ -100,7 +100,7 @@ static uint8_t max_priority;
static uint32_t rand_seed;
static uint64_t meter_profile_values[3]; /* CIR CBS EBS values. */
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define LCORE_MODE_PKT 1
#define LCORE_MODE_STATS 2
#define MAX_STREAMS 64
diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h
index 492b5757f113..229146a8d677 100644
--- a/app/test-pmd/testpmd.h
+++ b/app/test-pmd/testpmd.h
@@ -78,7 +78,7 @@ struct cmdline_file_info {
#define TX_DESC_MAX 2048
#define MAX_PKT_BURST 512
-#define DEF_PKT_BURST 32
+#define DEF_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define DEF_MBUF_CACHE 250
diff --git a/app/test/test_link_bonding.c b/app/test/test_link_bonding.c
index 19b064771aef..dd1b19104732 100644
--- a/app/test/test_link_bonding.c
+++ b/app/test/test_link_bonding.c
@@ -52,7 +52,7 @@
#define RX_DESC_MAX (2048)
#define TX_DESC_MAX (2048)
#define MAX_PKT_BURST (512)
-#define DEF_PKT_BURST (16)
+#define DEF_PKT_BURST (RTE_OPTIMAL_BURST_SIZE)
#define BONDING_DEV_NAME ("net_bonding_ut")
diff --git a/app/test/test_link_bonding_mode4.c b/app/test/test_link_bonding_mode4.c
index ff13dbed93f3..ec336f06848c 100644
--- a/app/test/test_link_bonding_mode4.c
+++ b/app/test/test_link_bonding_mode4.c
@@ -41,8 +41,8 @@
#define TEST_RX_DESC_MAX (2048)
#define TEST_TX_DESC_MAX (2048)
-#define MAX_PKT_BURST (32)
-#define DEF_PKT_BURST (16)
+#define MAX_PKT_BURST (RTE_OPTIMAL_BURST_SIZE)
+#define DEF_PKT_BURST (RTE_OPTIMAL_BURST_SIZE)
#define BONDING_DEV_NAME ("net_bonding_m4_bond_dev")
diff --git a/app/test/test_pmd_perf.c b/app/test/test_pmd_perf.c
index 995b0a6f20c4..be4ebdf4c3ad 100644
--- a/app/test/test_pmd_perf.c
+++ b/app/test/test_pmd_perf.c
@@ -17,7 +17,7 @@
#define NB_ETHPORTS_USED (1)
#define NB_SOCKETS (2)
#define MEMPOOL_CACHE_SIZE 250
-#define MAX_PKT_BURST (32)
+#define MAX_PKT_BURST (RTE_OPTIMAL_BURST_SIZE)
#define RX_DESC_DEFAULT (1024)
#define TX_DESC_DEFAULT (1024)
#define RTE_PORT_ALL (~(uint16_t)0x0)
diff --git a/app/test/test_security_inline_proto.c b/app/test/test_security_inline_proto.c
index 04ecfd02c6a1..40b579107008 100644
--- a/app/test/test_security_inline_proto.c
+++ b/app/test/test_security_inline_proto.c
@@ -44,7 +44,7 @@ test_inline_ipsec_sg(void)
#define NB_ETHPORTS_USED 1
#define MEMPOOL_CACHE_SIZE 32
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define RX_DESC_DEFAULT 1024
#define TX_DESC_DEFAULT 1024
#define RTE_PORT_ALL (~(uint16_t)0x0)
diff --git a/examples/bbdev_app/main.c b/examples/bbdev_app/main.c
index 03f15f91cc6b..453bab9758f6 100644
--- a/examples/bbdev_app/main.c
+++ b/examples/bbdev_app/main.c
@@ -39,7 +39,7 @@
#define LLR_1_BIT 0x81
#define LLR_0_BIT 0x7F
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define NB_MBUF 8191
#define MEMPOOL_CACHE_SIZE 256
diff --git a/examples/bond/main.c b/examples/bond/main.c
index 9f38b63cbbad..36e7e0f4b54d 100644
--- a/examples/bond/main.c
+++ b/examples/bond/main.c
@@ -52,7 +52,7 @@
#define NB_MBUF (1024*8)
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
#define BURST_RX_INTERVAL_NS (10) /* RX poll interval ~100ns */
diff --git a/examples/distributor/main.c b/examples/distributor/main.c
index ea44939fba04..977b80e03697 100644
--- a/examples/distributor/main.c
+++ b/examples/distributor/main.c
@@ -23,10 +23,10 @@
#define TX_RING_SIZE 1024
#define NUM_MBUFS ((64*1024)-1)
#define MBUF_CACHE_SIZE 128
-#define BURST_SIZE 64
+#define BURST_SIZE RTE_OPTIMAL_BURST_SIZE
#define SCHED_RX_RING_SZ 8192
#define SCHED_TX_RING_SZ 65536
-#define BURST_SIZE_TX 32
+#define BURST_SIZE_TX RTE_OPTIMAL_BURST_SIZE
#define RTE_LOGTYPE_DISTRAPP RTE_LOGTYPE_USER1
diff --git a/examples/dma/dmafwd.c b/examples/dma/dmafwd.c
index 5ba0aaa40b21..3f9d934cd1b4 100644
--- a/examples/dma/dmafwd.c
+++ b/examples/dma/dmafwd.c
@@ -15,7 +15,7 @@
/* size of ring used for software copying between rx and tx. */
#define RTE_LOGTYPE_DMA RTE_LOGTYPE_USER1
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define MEMPOOL_CACHE_SIZE 512
#define MIN_POOL_SIZE 65536U
#define CMD_LINE_OPT_PORTMASK_INDEX 1
diff --git a/examples/ethtool/ethtool-app/main.c b/examples/ethtool/ethtool-app/main.c
index 1f011a932166..183cbd714020 100644
--- a/examples/ethtool/ethtool-app/main.c
+++ b/examples/ethtool/ethtool-app/main.c
@@ -19,7 +19,7 @@
#include "ethapp.h"
#define MAX_PORTS RTE_MAX_ETHPORTS
-#define MAX_BURST_LENGTH 32
+#define MAX_BURST_LENGTH RTE_OPTIMAL_BURST_SIZE
#define PORT_RX_QUEUE_SIZE 1024
#define PORT_TX_QUEUE_SIZE 1024
#define PKTPOOL_EXTRA_SIZE 512
diff --git a/examples/ip_fragmentation/main.c b/examples/ip_fragmentation/main.c
index 1f841028442f..57bb0f52cb90 100644
--- a/examples/ip_fragmentation/main.c
+++ b/examples/ip_fragmentation/main.c
@@ -75,7 +75,7 @@
#define NB_MBUF 8192
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
/* Configure how many packets ahead to prefetch, when reading packets */
diff --git a/examples/ip_reassembly/main.c b/examples/ip_reassembly/main.c
index 25b904dbd44d..bf4d30d0ef20 100644
--- a/examples/ip_reassembly/main.c
+++ b/examples/ip_reassembly/main.c
@@ -44,8 +44,7 @@
#include <rte_ip_frag.h>
-#define MAX_PKT_BURST 32
-
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define RTE_LOGTYPE_IP_RSMBL RTE_LOGTYPE_USER1
diff --git a/examples/ipsec-secgw/ipsec-secgw.h b/examples/ipsec-secgw/ipsec-secgw.h
index b4ef4b6d04bc..939159dd32b0 100644
--- a/examples/ipsec-secgw/ipsec-secgw.h
+++ b/examples/ipsec-secgw/ipsec-secgw.h
@@ -11,8 +11,8 @@
#define NB_SOCKETS 4
-#define MAX_PKT_BURST 32
-#define MAX_PKT_BURST_VEC 256
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
+#define MAX_PKT_BURST_VEC RTE_OPTIMAL_BURST_SIZE
#define MAX_PKTS \
((MAX_PKT_BURST_VEC > MAX_PKT_BURST ? \
diff --git a/examples/ipv4_multicast/main.c b/examples/ipv4_multicast/main.c
index 1eed645d02e0..742151749bbe 100644
--- a/examples/ipv4_multicast/main.c
+++ b/examples/ipv4_multicast/main.c
@@ -54,7 +54,7 @@
/* allow max jumbo frame 9.5 KB */
#define JUMBO_FRAME_MAX_SIZE 0x2600
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
/* Configure how many packets ahead to prefetch, when reading packets */
diff --git a/examples/l2fwd-cat/l2fwd-cat.c b/examples/l2fwd-cat/l2fwd-cat.c
index 6e16705e9931..bac18496a7fb 100644
--- a/examples/l2fwd-cat/l2fwd-cat.c
+++ b/examples/l2fwd-cat/l2fwd-cat.c
@@ -17,7 +17,7 @@
#define NUM_MBUFS 8191
#define MBUF_CACHE_SIZE 250
-#define BURST_SIZE 32
+#define BURST_SIZE RTE_OPTIMAL_BURST_SIZE
/* l2fwd-cat.c: CAT enabled, basic DPDK skeleton forwarding example. */
diff --git a/examples/l2fwd-crypto/main.c b/examples/l2fwd-crypto/main.c
index a441312f5524..bfe0b662a5ed 100644
--- a/examples/l2fwd-crypto/main.c
+++ b/examples/l2fwd-crypto/main.c
@@ -61,7 +61,7 @@ enum cdev_type {
#define MAX_KEY_SIZE 128
#define MAX_IV_SIZE 16
#define MAX_AAD_SIZE 65535
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
#define SESSION_POOL_CACHE_SIZE 0
diff --git a/examples/l2fwd-event/l2fwd_common.h b/examples/l2fwd-event/l2fwd_common.h
index 8cf91b919cd4..2f271ac06972 100644
--- a/examples/l2fwd-event/l2fwd_common.h
+++ b/examples/l2fwd-event/l2fwd_common.h
@@ -42,7 +42,7 @@
#include <rte_mbuf.h>
#include <rte_spinlock.h>
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define MAX_RX_QUEUE_PER_LCORE 16
#define MAX_TX_QUEUE_PER_PORT 16
diff --git a/examples/l2fwd-jobstats/main.c b/examples/l2fwd-jobstats/main.c
index 308b8edd2023..7018d2b7e185 100644
--- a/examples/l2fwd-jobstats/main.c
+++ b/examples/l2fwd-jobstats/main.c
@@ -39,7 +39,7 @@
#define NB_MBUF 8192
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
/*
diff --git a/examples/l2fwd-keepalive/main.c b/examples/l2fwd-keepalive/main.c
index bff2b99531aa..29ce52580678 100644
--- a/examples/l2fwd-keepalive/main.c
+++ b/examples/l2fwd-keepalive/main.c
@@ -43,7 +43,7 @@
#define NB_MBUF_PER_PORT 3000
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
/*
diff --git a/examples/l2fwd-macsec/main.c b/examples/l2fwd-macsec/main.c
index 73e32fc197b6..dcfa97896a7e 100644
--- a/examples/l2fwd-macsec/main.c
+++ b/examples/l2fwd-macsec/main.c
@@ -49,7 +49,7 @@ static int promiscuous_on = 1;
#define RTE_LOGTYPE_L2FWD RTE_LOGTYPE_USER1
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
#define MEMPOOL_CACHE_SIZE 256
#define SESSION_POOL_CACHE_SIZE 0
diff --git a/examples/l2fwd/main.c b/examples/l2fwd/main.c
index c6fafdd01935..c98350f58fba 100644
--- a/examples/l2fwd/main.c
+++ b/examples/l2fwd/main.c
@@ -48,7 +48,7 @@ static int promiscuous_on;
#define RTE_LOGTYPE_L2FWD RTE_LOGTYPE_USER1
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
#define MEMPOOL_CACHE_SIZE 256
diff --git a/examples/l3fwd-power/main.c b/examples/l3fwd-power/main.c
index ec12d1cc0b73..46dbefaebbb2 100644
--- a/examples/l3fwd-power/main.c
+++ b/examples/l3fwd-power/main.c
@@ -55,7 +55,7 @@
RTE_LOG_REGISTER(l3fwd_power_logtype, l3fwd.power, INFO);
#define RTE_LOGTYPE_L3FWD_POWER l3fwd_power_logtype
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define MIN_ZERO_POLL_COUNT 10
diff --git a/examples/l3fwd/l3fwd.h b/examples/l3fwd/l3fwd.h
index 471e3b488fe6..0fa166c6d528 100644
--- a/examples/l3fwd/l3fwd.h
+++ b/examples/l3fwd/l3fwd.h
@@ -23,14 +23,14 @@
#define RX_DESC_DEFAULT 1024
#define TX_DESC_DEFAULT 1024
-#define DEFAULT_PKT_BURST 32
+#define DEFAULT_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define MAX_PKT_BURST 512
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
#define MEMPOOL_CACHE_SIZE RTE_MEMPOOL_CACHE_MAX_SIZE
#define MAX_RX_QUEUE_PER_LCORE 16
-#define VECTOR_SIZE_DEFAULT MAX_PKT_BURST
+#define VECTOR_SIZE_DEFAULT RTE_OPTIMAL_BURST_SIZE
#define VECTOR_TMO_NS_DEFAULT 1E6 /* 1ms */
#define NB_SOCKETS 8
diff --git a/examples/l3fwd/main.c b/examples/l3fwd/main.c
index a5626ff02d13..00375a74fbe7 100644
--- a/examples/l3fwd/main.c
+++ b/examples/l3fwd/main.c
@@ -1074,17 +1074,26 @@ parse_args(int argc, char **argv)
return -1;
}
- if (evt_rsrc->vector_enabled && !evt_rsrc->vector_size) {
- evt_rsrc->vector_size = VECTOR_SIZE_DEFAULT;
- fprintf(stderr, "vector size set to default (%" PRIu16 ")\n",
- evt_rsrc->vector_size);
+ if (evt_rsrc->vector_enabled) {
+ if (!evt_rsrc->vector_size) {
+ evt_rsrc->vector_size = VECTOR_SIZE_DEFAULT;
+ fprintf(stderr, "vector size set to default (%" PRIu16 ")\n",
+ evt_rsrc->vector_size);
+ } else {
+ fprintf(stderr, "vector size set to (%" PRIu16 ")\n",
+ evt_rsrc->vector_size);
+ }
}
- if (evt_rsrc->vector_enabled && !evt_rsrc->vector_tmo_ns) {
- evt_rsrc->vector_tmo_ns = VECTOR_TMO_NS_DEFAULT;
- fprintf(stderr,
- "vector timeout set to default (%" PRIu64 " ns)\n",
- evt_rsrc->vector_tmo_ns);
+ if (evt_rsrc->vector_enabled) {
+ if (!evt_rsrc->vector_tmo_ns) {
+ evt_rsrc->vector_tmo_ns = VECTOR_TMO_NS_DEFAULT;
+ fprintf(stderr, "vector timeout set to default (%" PRIu64 " ns)\n",
+ evt_rsrc->vector_tmo_ns);
+ } else {
+ fprintf(stderr, "vector timeout set to (%" PRIu64 " ns)\n",
+ evt_rsrc->vector_tmo_ns);
+ }
}
#endif
@@ -1687,7 +1696,9 @@ main(int argc, char **argv)
if (ret < 0)
rte_exit(EXIT_FAILURE, "Invalid L3FWD parameters\n");
+#ifndef RTE_LIB_EVENTDEV
RTE_LOG(INFO, L3FWD, "Using Rx burst %u Tx burst %u\n", rx_burst_size, tx_burst_size);
+#endif
/* Setup function pointers for lookup method. */
setup_l3fwd_lookup_tables();
diff --git a/examples/link_status_interrupt/main.c b/examples/link_status_interrupt/main.c
index ac9c7f62170e..2cf8e3f67f91 100644
--- a/examples/link_status_interrupt/main.c
+++ b/examples/link_status_interrupt/main.c
@@ -39,7 +39,7 @@
#define NB_MBUF 8192
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
/*
@@ -61,7 +61,7 @@ static unsigned int lsi_rx_queue_per_lcore = 1;
/* destination port for L2 forwarding */
static unsigned lsi_dst_ports[RTE_MAX_ETHPORTS] = {0};
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define MAX_RX_QUEUE_PER_LCORE 16
#define MAX_TX_QUEUE_PER_PORT 16
diff --git a/examples/multi_process/symmetric_mp/main.c b/examples/multi_process/symmetric_mp/main.c
index f7d8439cd4e6..1780e93fd742 100644
--- a/examples/multi_process/symmetric_mp/main.c
+++ b/examples/multi_process/symmetric_mp/main.c
@@ -46,7 +46,7 @@
#define NB_MBUFS 64*1024 /* use 64k mbufs */
#define MBUF_CACHE_SIZE 256
-#define PKT_BURST 32
+#define PKT_BURST RTE_OPTIMAL_BURST_SIZE
#define RX_RING_SIZE 1024
#define TX_RING_SIZE 1024
diff --git a/examples/ntb/ntb_fwd.c b/examples/ntb/ntb_fwd.c
index 33f3c1ef17e4..5e7629753089 100644
--- a/examples/ntb/ntb_fwd.c
+++ b/examples/ntb/ntb_fwd.c
@@ -83,8 +83,8 @@ static uint16_t nb_desc = NTB_DEFAULT_NUM_DESCS;
static uint16_t tx_free_thresh;
-#define NTB_MAX_PKT_BURST 32
-#define NTB_DFLT_PKT_BURST 32
+#define NTB_MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
+#define NTB_DFLT_PKT_BURST RTE_OPTIMAL_BURST_SIZE
static uint16_t pkt_burst = NTB_DFLT_PKT_BURST;
#define BURST_TX_RETRIES 64
diff --git a/examples/packet_ordering/main.c b/examples/packet_ordering/main.c
index 5ffdf72d71ab..a2092930523a 100644
--- a/examples/packet_ordering/main.c
+++ b/examples/packet_ordering/main.c
@@ -21,7 +21,7 @@
#define RX_DESC_PER_QUEUE 1024
#define TX_DESC_PER_QUEUE 1024
-#define MAX_PKTS_BURST 32
+#define MAX_PKTS_BURST RTE_OPTIMAL_BURST_SIZE
#define REORDER_BUFFER_SIZE 8192
#define MBUF_PER_POOL 65535
#define MBUF_POOL_CACHE_SIZE 250
diff --git a/examples/qos_meter/main.c b/examples/qos_meter/main.c
index da1b0b228787..cdfdfde82aec 100644
--- a/examples/qos_meter/main.c
+++ b/examples/qos_meter/main.c
@@ -76,8 +76,8 @@ static struct rte_eth_conf port_conf = {
* Packet RX/TX
*
***/
-#define RTE_MBUF_F_RX_BURST_MAX 32
-#define RTE_MBUF_F_TX_BURST_MAX 32
+#define RTE_MBUF_F_RX_BURST_MAX RTE_OPTIMAL_BURST_SIZE
+#define RTE_MBUF_F_TX_BURST_MAX RTE_OPTIMAL_BURST_SIZE
#define TIME_TX_DRAIN 200000ULL
static uint16_t port_rx;
diff --git a/examples/qos_sched/main.h b/examples/qos_sched/main.h
index ea66df0434fb..58abd5b9c4e2 100644
--- a/examples/qos_sched/main.h
+++ b/examples/qos_sched/main.h
@@ -24,10 +24,10 @@ extern "C" {
#define APP_RING_SIZE (8*1024)
#define NB_MBUF (2*1024*1024)
-#define MAX_PKT_RX_BURST 64
+#define MAX_PKT_RX_BURST RTE_OPTIMAL_BURST_SIZE
#define PKT_ENQUEUE 64
#define PKT_DEQUEUE 63
-#define MAX_PKT_TX_BURST 64
+#define MAX_PKT_TX_BURST RTE_OPTIMAL_BURST_SIZE
#define RX_PTHRESH 8 /**< Default values of RX prefetch threshold reg. */
#define RX_HTHRESH 8 /**< Default values of RX host threshold reg. */
diff --git a/examples/rxtx_callbacks/main.c b/examples/rxtx_callbacks/main.c
index 4682921285de..8b01248f286d 100644
--- a/examples/rxtx_callbacks/main.c
+++ b/examples/rxtx_callbacks/main.c
@@ -19,7 +19,7 @@
#define NUM_MBUFS 8191
#define MBUF_CACHE_SIZE 250
-#define BURST_SIZE 32
+#define BURST_SIZE RTE_OPTIMAL_BURST_SIZE
static int hwts_dynfield_offset = -1;
diff --git a/examples/skeleton/basicfwd.c b/examples/skeleton/basicfwd.c
index 133293cf15bb..28ab971f56db 100644
--- a/examples/skeleton/basicfwd.c
+++ b/examples/skeleton/basicfwd.c
@@ -16,7 +16,7 @@
#define NUM_MBUFS 8191
#define MBUF_CACHE_SIZE 250
-#define BURST_SIZE 32
+#define BURST_SIZE RTE_OPTIMAL_BURST_SIZE
/* basicfwd.c: Basic DPDK skeleton forwarding example. */
diff --git a/examples/vhost/main.h b/examples/vhost/main.h
index c986cbc5a994..b85c251037d0 100644
--- a/examples/vhost/main.h
+++ b/examples/vhost/main.h
@@ -17,7 +17,7 @@
enum {VIRTIO_RXQ, VIRTIO_TXQ, VIRTIO_QNUM};
-#define MAX_PKT_BURST 32 /* Max burst size for RX/TX */
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE /* Max burst size for RX/TX */
struct device_statistics {
uint64_t tx;
diff --git a/examples/vhost_crypto/main.c b/examples/vhost_crypto/main.c
index 8bdfc40c4b20..d60e17bee7d0 100644
--- a/examples/vhost_crypto/main.c
+++ b/examples/vhost_crypto/main.c
@@ -23,7 +23,7 @@
#include <cmdline.h>
#define NB_VIRTIO_QUEUES (1)
-#define MAX_PKT_BURST (64)
+#define MAX_PKT_BURST (RTE_OPTIMAL_BURST_SIZE)
#define MAX_IV_LEN (32)
#define NB_MEMPOOL_OBJS (8192)
#define NB_CRYPTO_DESCRIPTORS (4096)
diff --git a/examples/vm_power_manager/main.c b/examples/vm_power_manager/main.c
index c14138202004..839348bb75d6 100644
--- a/examples/vm_power_manager/main.c
+++ b/examples/vm_power_manager/main.c
@@ -45,7 +45,7 @@
#define NUM_MBUFS 8191
#define MBUF_CACHE_SIZE 250
-#define BURST_SIZE 32
+#define BURST_SIZE RTE_OPTIMAL_BURST_SIZE
static uint32_t enabled_port_mask;
static volatile bool force_quit;
diff --git a/examples/vmdq/main.c b/examples/vmdq/main.c
index 4a3ce6884c5c..19af8b052adf 100644
--- a/examples/vmdq/main.c
+++ b/examples/vmdq/main.c
@@ -42,7 +42,7 @@
TX_DESC_DEFAULT))
#define MBUF_CACHE_SIZE 64
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
/*
* Configurable number of RX/TX ring descriptors
diff --git a/examples/vmdq_dcb/main.c b/examples/vmdq_dcb/main.c
index 4ccc2fe4b01c..94b077ccbc75 100644
--- a/examples/vmdq_dcb/main.c
+++ b/examples/vmdq_dcb/main.c
@@ -43,7 +43,7 @@
TX_DESC_DEFAULT))
#define MBUF_CACHE_SIZE 64
-#define MAX_PKT_BURST 32
+#define MAX_PKT_BURST RTE_OPTIMAL_BURST_SIZE
/*
* Configurable number of RX/TX ring descriptors
--
2.50.1 (Apple Git-155)
^ permalink raw reply [flat|nested] 5+ messages in thread* RE: [RFC 1/2] config: add optimal burst size configuration
2025-11-26 8:24 [RFC 1/2] config: add optimal burst size configuration pbhagavatula
2025-11-26 8:24 ` [RFC 2/2] examples: use optimal burst size pbhagavatula
@ 2025-11-26 9:57 ` Morten Brørup
2025-11-26 10:58 ` Pavan Nikhilesh Bhagavatula
2025-11-26 11:00 ` Pavan Nikhilesh Bhagavatula
1 sibling, 2 replies; 5+ messages in thread
From: Morten Brørup @ 2025-11-26 9:57 UTC (permalink / raw)
To: Pavan Nikhilesh, Jerin Jacob, Wathsala Vithanage, Bruce Richardson; +Cc: dev
> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>
> Add RTE_OPTIMAL_BURST_SIZE to allow platforms to configure the
> optimal burst size.
>
> Set default value to 64 for soc_cn10k and 32 generally.
>
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> ---
> This improves performance by 5% on l2fwd, other examples showed
> negligible difference on CN10K.
>
I support the concept of having a recommended mbuf burst size, targeting the majority of generic applications.
Making it CPU dependent seems like a good choice.
It should be named differently.
First of all, "optimal" depends on the use case; if targeting low latency, shorter bursts are better, so "OPTIMAL" should not be part of the name.
Second, I would guess that it only targets mbuf bursts, not also bursts of other operations (e.g. hash lookups), so "MBUF" should be part of the name.
Suggestion:
/* Recommended burst size for generic applications, striking a balance between throughput and latency. */
dpdk_conf.set('RTE_MBUF_BURST_SIZE_MAX' (or _DEFAULT), 64)
<feature creep>
/* Recommended burst size for generic applications targeting low latency. */
dpdk_conf.set('RTE_MBUF_BURST_SIZE_MIN', 4)
</feature creep>
Having these standardized will also allow libraries and drivers to optimize for them, e.g. drivers should support bursts sizes all the way down to RTE_MBUF_BURST_SIZE_MIN, and can static_assert() that the RTE_MBUF_BURST_SIZE_MIN is not lower than supported by the driver/hardware.
<more feature creep>
rte_config.h could have "#define RTE_MBUF_BURST_SIZE RTE_MBUF_BURST_SIZE_MAX", for the application developer to change to RTE_MBUF_BURST_SIZE_MIN for low latency applications.
This will let the libraries and drivers optimize for the specific burst size used by the application.
</more feature creep>
<rambling>
Intuitively, I would assume that the optimal burst size essentially depends on the CPU's L1D cache size and the application's number of non-mbuf cache lines accessed per burst.
Let's say a CPU core has 32 KiB cache (= 512 cache lines), and each burst touches 4 cache lines per packet:
2 cache lines for the mbuf
1 cache line for the packet data
1 cache line per packet for some table lookup/forwarding entry
Then the mbuf burst should be max 512/4 = 128.
But local variables also use memory during processing, so using a burst of 64 would leave room for that and some more.
</rambling>
> config/arm/meson.build | 1 +
> config/meson.build | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/config/arm/meson.build b/config/arm/meson.build
> index 523b0fc0ed50..fa64c07016b1 100644
> --- a/config/arm/meson.build
> +++ b/config/arm/meson.build
> @@ -481,6 +481,7 @@ soc_cn10k = {
> ['RTE_MAX_LCORE', 24],
> ['RTE_MAX_NUMA_NODES', 1],
> ['RTE_MEMPOOL_ALIGN', 128],
> + ['RTE_OPTIMAL_BURST_SIZE', 64],
> ],
> 'part_number': '0xd49',
> 'extra_march_features': ['crypto'],
> diff --git a/config/meson.build b/config/meson.build
> index 0cb074ab95b7..95367ae88e2d 100644
> --- a/config/meson.build
> +++ b/config/meson.build
> @@ -386,6 +386,7 @@ if get_option('mbuf_refcnt_atomic')
> dpdk_conf.set('RTE_MBUF_REFCNT_ATOMIC', true)
> endif
> dpdk_conf.set10('RTE_IOVA_IN_MBUF', get_option('enable_iova_as_pa'))
> +dpdk_conf.set('RTE_OPTIMAL_BURST_SIZE', 32)
>
> compile_time_cpuflags = []
> subdir(arch_subdir)
> --
> 2.50.1 (Apple Git-155)
^ permalink raw reply [flat|nested] 5+ messages in thread