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David S. Miller a8ff736d31 Merge branch 'page_pool-stats'
Joe Damato says:

====================
page_pool: Add stats counters

Greetings:

Welcome to v9.

This revisions adds a commit which updates the page_pool documentation to
describe the stats API, structures, and fields.

Additionally, this revision contains a minor cosmetic change suggested by
Saeed in page_pool_recycle_in_ring in commit 2: "page_pool: Add recycle
stats", which removes an unnecessary #ifdef.

There are no functional changes in this revision.

Benchmark output from the v7 cover [1] is pasted below, as it is still
relevant since no functional changes have been made in this revision:

Benchmarks have been re-run. As always, results between runs are highly
variable; you'll find results showing that stats disabled are both faster
and slower than stats enabled in back to back benchmark runs.

Raw benchmark output with stats off [2] and stats on [3] are available for
examination.

Test system:
	- 2x Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz
	- 2 NUMA zones, with 18 cores per zone and 2 threads per core

bench_page_pool_simple results, loops=200000000
test name			stats enabled		stats disabled
				cycles	nanosec		cycles	nanosec

for_loop			0	0.335		0	0.336
atomic_inc 			14	6.106		13	6.022
lock				30	13.365		32	13.968

no-softirq-page_pool01		75	32.884		74	32.308
no-softirq-page_pool02		79	34.696		74	32.302
no-softirq-page_pool03		110	48.005		105	46.073

tasklet_page_pool01_fast_path	14	6.156		14	6.211
tasklet_page_pool02_ptr_ring	41	18.028		39	17.391
tasklet_page_pool03_slow	107	46.646		105	46.123

bench_page_pool_cross_cpu results, loops=20000000 returning_cpus=4:
test name			stats enabled		stats disabled
				cycles	nanosec		cycles	nanosec

page_pool_cross_cpu CPU(0)	3973	1731.596	4015	1750.015
page_pool_cross_cpu CPU(1)	3976	1733.217	4022	1752.864
page_pool_cross_cpu CPU(2)	3973	1731.615	4016	1750.433
page_pool_cross_cpu CPU(3)	3976	1733.218	4021	1752.806
page_pool_cross_cpu CPU(4)	994	433.305		1005	438.217

page_pool_cross_cpu average	3378	-		3415	-

bench_page_pool_cross_cpu results, loops=20000000 returning_cpus=8:
test name			stats enabled		stats disabled
				cycles	nanosec		cycles	nanosec

page_pool_cross_cpu CPU(0)	6969	3037.488	6909	3011.463
page_pool_cross_cpu CPU(1)	6974	3039.469	6913	3012.961
page_pool_cross_cpu CPU(2)	6969	3037.575	6910	3011.585
page_pool_cross_cpu CPU(3)	6974	3039.415	6913	3012.961
page_pool_cross_cpu CPU(4)	6969	3037.288	6909	3011.368
page_pool_cross_cpu CPU(5)	6972	3038.732	6913	3012.920
page_pool_cross_cpu CPU(6)	6969	3037.350	6909	3011.386
page_pool_cross_cpu CPU(7)	6973	3039.356	6913	3012.921
page_pool_cross_cpu CPU(8)	871	379.934		864	376.620

page_pool_cross_cpu average	6293	-		6239	-

Thanks.

[1]: https://lore.kernel.org/all/1645810914-35485-1-git-send-email-jdamato@fastly.com/
[2]: https://gist.githubusercontent.com/jdamato-fsly/d7c34b9fa7be1ce132a266b0f2b92aea/raw/327dcd71d11ece10238fbf19e0472afbcbf22fd4/v7_stats_disabled
[3]: https://gist.githubusercontent.com/jdamato-fsly/d7c34b9fa7be1ce132a266b0f2b92aea/raw/327dcd71d11ece10238fbf19e0472afbcbf22fd4/v7_stats_enabled

v8 -> v9:
	- Add documentation about the page_pool_get_stats API, stats
	  structures, and fields to Documentation/networking/page_pool.rst.
	- Remove unnecessary #ifdef in page_pool_recycle_in_ring.

v7 -> v8:
	- Rename mlx5 ethtool stats so that users have a better idea of
	  their meaning.

v6 -> v7:
	- stats split out into two structs one single per-page pool struct
	  for allocation path stats and one per-cpu pointer for recycle
	  path stats.
	- page_pool_get_stats updated to use a wrapper struct to gather
	  stats for allocation and recycle stats with a single argument.
	- placement of structs adjusted
	- mlx5 driver modified to use page_pool_get_stats API

v5 -> v6:
	- Per cpu page_pool_stats struct pointer is now marked as
	  ____cacheline_aligned_in_smp. Placement of the field in the
	  struct is unchanged; it is the last field.

v4 -> v5:
	- Fixed the description of the kernel option in Kconfig.
	- Squashed commits 1-10 from v4 into a single commit for easier
	  review.
	- Changed the comment style of the comment for
	  the this_cpu_inc_alloc_stat macro.
	- Changed the return type of page_pool_get_stats from struct
	  page_pool_stat * to bool.

v3 -> v4:
	- Restructured stats to be per-cpu per-pool.
	- Global stats and proc file were removed.
	- Exposed an API (page_pool_get_stats) for batching the pool stats.

v2 -> v3:
	- patch 8/10 ("Add stat tracking cache refill") fixed placement of
	  counter increment.
	- patch 10/10 ("net-procfs: Show page pool stats in proc") updated:
		- fix unused label warning from kernel test robot,
		- fixed page_pool_seq_show to only display the refill stat
		  once,
		- added a remove_proc_entry for page_pool_stat to
		  dev_proc_net_exit.

v1 -> v2:
	- A new kernel config option has been added, which defaults to N,
	   preventing this code from being compiled in by default
	- The stats structure has been converted to a per-cpu structure
	- The stats are now exported via proc (/proc/net/page_pool_stat)
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
History 2022-03-03 09:55:28 +00:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-24 17:54:25 -08:00
block block: clear iocb->private in blkdev_bio_end_io_async() 2022-02-22 06:59:49 -07:00
certs certs: Fix build error when CONFIG_MODULE_SIG_KEY is empty 2022-01-23 00:08:44 +09:00
crypto crypto: af_alg - get rid of alg_memory_allocated 2022-02-15 14:29:04 +00:00
Documentation Documentation: update networking/page_pool.rst 2022-03-03 09:55:28 +00:00
drivers mlx5: add support for page_pool_get_stats 2022-03-03 09:55:28 +00:00
fs io_uring-5.17-2022-02-23 2022-02-24 11:08:15 -08:00
include page_pool: Add function to batch and return stats 2022-03-03 09:55:28 +00:00
init Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2022-02-09 18:40:56 -08:00
ipc ipc/sem: do not sleep with a spin lock held 2022-02-04 09:25:05 -08:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-24 17:54:25 -08:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-24 17:54:25 -08:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: don't try to NUMA-migrate COW pages that have other uses 2022-02-17 08:57:47 -08:00
net page_pool: Add function to batch and return stats 2022-03-03 09:55:28 +00:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-17 11:44:20 -08:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-17 11:44:20 -08:00
security rtnetlink: add new rtm tunnel api for tunnel id filtering 2022-03-01 08:38:02 +00:00
sound spi: Make remove() return void 2022-02-28 10:43:07 -08:00
tools selftests: add new tests for vxlan vnifiltering 2022-03-01 08:38:02 +00:00
usr kbuild: remove include/linux/cyclades.h from header file check 2022-01-27 08:51:08 +01:00
virt Two larger x86 series: 2022-01-28 19:00:26 +02:00
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: update Christian Brauner's email address 2022-02-01 11:21:31 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Removing Ohad from remoteproc/rpmsg maintenance 2021-12-08 10:09:40 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS net/fungible: Kconfig, Makefiles, and MAINTAINERS 2022-02-27 10:51:23 +00:00
Makefile Linux 5.17-rc5 2022-02-20 13:07:20 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.