From: Vladyslav Buslov <vladyslav.buslov@harmonicinc.com>
To: <helin.zhang@intel.com>, <jingjing.wu@intel.com>
Cc: <dev@dpdk.org>
Subject: [dpdk-dev] [PATCH] Add missing prefetches to i40e bulk rx path
Date: Thu, 14 Jul 2016 20:27:18 +0300 [thread overview]
Message-ID: <20160714172719.17502-1-vladyslav.buslov@harmonicinc.com> (raw)
Hello,
Recently I tried to use bulk rx function to reduce CPU usage of rte_eth_rx_burst.
However application performance with i40e_recv_pkts_bulk_alloc was significantly worse than with i40e_recv_pkts. (3m less PPS, 0.5 IPC on receiving core)
Quick investigation revealed two problems:
- First payload cacheline is prefetched in i40e_recv_pkts but not in i40e_recv_pkts_bulk_alloc.
- Only first line of next mbuf is prefetched during mbuf init in i40e_rx_alloc_bufs. This causes cache miss at setting 'next' field from mbuf cacheline1 to NULL.
Fixing these two small issues significantly reduced CPU time spent in rte_eth_rx_burst and improved PPS compared to both original i40e_recv_pkts_bulk_alloc and i40e_recv_pkts.
Regards,
Vladyslav Buslov (1):
net/i40e: add additional prefetch instructions for bulk rx
drivers/net/i40e/i40e_rxtx.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--
2.8.3
next reply other threads:[~2016-07-14 17:27 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-14 17:27 Vladyslav Buslov [this message]
2016-07-14 17:27 ` [dpdk-dev] [PATCH] net/i40e: add additional prefetch instructions for bulk rx Vladyslav Buslov
2016-09-14 13:24 ` Ferruh Yigit
2016-10-10 13:25 ` Wu, Jingjing
2016-10-10 17:05 ` Vladyslav Buslov
2016-10-11 8:51 ` Ananyev, Konstantin
2016-10-11 9:24 ` Vladyslav Buslov
2016-10-12 0:04 ` Ananyev, Konstantin
2016-10-13 10:18 ` Bruce Richardson
2016-10-13 10:30 ` Ananyev, Konstantin
2016-11-15 12:19 ` Ferruh Yigit
2016-11-15 13:27 ` Vladyslav Buslov
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