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v0.6.0
https://github.com/torvalds/linux
Revision a0783cd0c810504427777e8aae20d5f4f8b652a0 authored by Corinna Vinschen on 19 November 2019, 09:09:39 UTC, committed by David S. Miller on 20 November 2019, 00:41:11 UTC
During performance testing, I found that one of my r8169 NICs suffered
a major performance loss, a 8168c model.

Running netperf's TCP_STREAM test didn't return the expected
throughput of > 900 Mb/s, but rather only about 22 Mb/s.  Strange
enough, running the TCP_MAERTS and UDP_STREAM tests all returned with
throughput > 900 Mb/s, as did TCP_STREAM with the other r8169 NICs I can
test (either one of 8169s, 8168e, 8168f).

Bisecting turned up commit 93681cd7d94f83903cb3f0f95433d10c28a7e9a5,
"r8169: enable HW csum and TSO" as the culprit.

I added my 8168c version, RTL_GIGA_MAC_VER_22, to the code
special-casing the 8168evl as per the patch below.  This fixed the
performance problem for me.

Fixes: 93681cd7d94f ("r8169: enable HW csum and TSO")
Signed-off-by: Corinna Vinschen <vinschen@redhat.com>
Reviewed-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent c9d55b6
Raw File
Tip revision: a0783cd0c810504427777e8aae20d5f4f8b652a0 authored by Corinna Vinschen on 19 November 2019, 09:09:39 UTC
r8169: disable TSO on a single version of RTL8168c to fix performance
Tip revision: a0783cd
Kconfig.debug
# SPDX-License-Identifier: GPL-2.0-only
#
# RCU-related debugging configuration options
#

menu "RCU Debugging"

config PROVE_RCU
	def_bool PROVE_LOCKING

config PROVE_RCU_LIST
	bool "RCU list lockdep debugging"
	depends on PROVE_RCU && RCU_EXPERT
	default n
	help
	  Enable RCU lockdep checking for list usages. By default it is
	  turned off since there are several list RCU users that still
	  need to be converted to pass a lockdep expression. To prevent
	  false-positive splats, we keep it default disabled but once all
	  users are converted, we can remove this config option.

config TORTURE_TEST
	tristate
	default n

config RCU_PERF_TEST
	tristate "performance tests for RCU"
	depends on DEBUG_KERNEL
	select TORTURE_TEST
	select SRCU
	select TASKS_RCU
	default n
	help
	  This option provides a kernel module that runs performance
	  tests on the RCU infrastructure.  The kernel module may be built
	  after the fact on the running kernel to be tested, if desired.

	  Say Y here if you want RCU performance tests to be built into
	  the kernel.
	  Say M if you want the RCU performance tests to build as a module.
	  Say N if you are unsure.

config RCU_TORTURE_TEST
	tristate "torture tests for RCU"
	depends on DEBUG_KERNEL
	select TORTURE_TEST
	select SRCU
	select TASKS_RCU
	default n
	help
	  This option provides a kernel module that runs torture tests
	  on the RCU infrastructure.  The kernel module may be built
	  after the fact on the running kernel to be tested, if desired.

	  Say Y here if you want RCU torture tests to be built into
	  the kernel.
	  Say M if you want the RCU torture tests to build as a module.
	  Say N if you are unsure.

config RCU_CPU_STALL_TIMEOUT
	int "RCU CPU stall timeout in seconds"
	depends on RCU_STALL_COMMON
	range 3 300
	default 21
	help
	  If a given RCU grace period extends more than the specified
	  number of seconds, a CPU stall warning is printed.  If the
	  RCU grace period persists, additional CPU stall warnings are
	  printed at more widely spaced intervals.

config RCU_TRACE
	bool "Enable tracing for RCU"
	depends on DEBUG_KERNEL
	default y if TREE_RCU
	select TRACE_CLOCK
	help
	  This option enables additional tracepoints for ftrace-style
	  event tracing.

	  Say Y here if you want to enable RCU tracing
	  Say N if you are unsure.

config RCU_EQS_DEBUG
	bool "Provide debugging asserts for adding NO_HZ support to an arch"
	depends on DEBUG_KERNEL
	help
	  This option provides consistency checks in RCU's handling of
	  NO_HZ.  These checks have proven quite helpful in detecting
	  bugs in arch-specific NO_HZ code.

	  Say N here if you need ultimate kernel/user switch latencies
	  Say Y if you are unsure

endmenu # "RCU Debugging"
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