mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-30 14:19:16 +00:00
4aaf2c5283
When running workloads heavy unbalanced towards TX (high TX, low RX traffic), sfc driver can retain the CPU during too long times. Although in many cases this is not enough to be visible, it can affect performance and system responsiveness. A way to reproduce it is to use a debug kernel and run some parallel netperf TX tests. In some systems, this will lead to this message being logged: kernel:watchdog: BUG: soft lockup - CPU#12 stuck for 22s! The reason is that sfc driver doesn't account any NAPI budget for the TX completion events work. With high-TX/low-RX traffic, this makes that the CPU is held for long time for NAPI poll. Documentations says "drivers can process completions for any number of Tx packets but should only process up to budget number of Rx packets". However, many drivers do limit the amount of TX completions that they process in a single NAPI poll. In the same way, this patch adds a limit for the TX work in sfc. With the patch applied, the watchdog warning never appears. Tested with netperf in different combinations: single process / parallel processes, TCP / UDP and different sizes of UDP messages. Repeated the tests before and after the patch, without any noticeable difference in network or CPU performance. Test hardware: Intel(R) Xeon(R) CPU E5-1620 v4 @ 3.50GHz (4 cores, 2 threads/core) Solarflare Communications XtremeScale X2522-25G Network Adapter Fixes:5227ecccea("sfc: remove tx and MCDI handling from NAPI budget consideration") Fixes:d19a537218("sfc_ef100: TX path for EF100 NICs") Reported-by: Fei Liu <feliu@redhat.com> Signed-off-by: Íñigo Huguet <ihuguet@redhat.com> Acked-by: Martin Habets <habetsm.xilinx@gmail.com> Link: https://lore.kernel.org/r/20230615084929.10506-1-ihuguet@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
28 lines
1 KiB
C
28 lines
1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/****************************************************************************
|
|
* Driver for Solarflare network controllers and boards
|
|
* Copyright 2019 Solarflare Communications Inc.
|
|
* Copyright 2019-2020 Xilinx Inc.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 as published
|
|
* by the Free Software Foundation, incorporated herein by reference.
|
|
*/
|
|
|
|
#ifndef EFX_EF100_TX_H
|
|
#define EFX_EF100_TX_H
|
|
|
|
#include "net_driver.h"
|
|
#include "ef100_rep.h"
|
|
|
|
int ef100_tx_probe(struct efx_tx_queue *tx_queue);
|
|
void ef100_tx_init(struct efx_tx_queue *tx_queue);
|
|
void ef100_tx_write(struct efx_tx_queue *tx_queue);
|
|
unsigned int ef100_tx_max_skb_descs(struct efx_nic *efx);
|
|
|
|
int ef100_ev_tx(struct efx_channel *channel, const efx_qword_t *p_event);
|
|
|
|
netdev_tx_t ef100_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb);
|
|
int __ef100_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb,
|
|
struct efx_rep *efv);
|
|
#endif
|