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Simon Horman 4d86d38186 ravb: RX checksum offload
Add support for RX checksum offload. This is enabled by default and
may be disabled and re-enabled using ethtool:

 # ethtool -K eth0 rx off
 # ethtool -K eth0 rx on

The RAVB provides a simple checksumming scheme which appears to be
completely compatible with CHECKSUM_COMPLETE: sum of all packet data after
the L2 header is appended to packet data; this may be trivially read by the
driver and used to update the skb accordingly.

In terms of performance throughput is close to gigabit line-rate both with
and without RX checksum offload enabled. Perf output, however, appears to
indicate that significantly less time is spent in do_csum(). This is as
expected.

Test results with RX checksum offload enabled:
 # /usr/bin/perf_3.16 record -o /run/perf.data -a netperf -t TCP_MAERTS -H 10.4.3.162
 MIGRATED TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.4.3.162 () port 0 AF_INET : demo
 enable_enobufs failed: getprotobyname
 Recv   Send    Send
 Socket Socket  Message  Elapsed
 Size   Size    Size     Time     Throughput
 bytes  bytes   bytes    secs.    10^6bits/sec

  87380  16384  16384    10.00     937.54

 Summary of output of perf report:
    18.28%      ksoftirqd/0  [kernel.kallsyms]  [k] _raw_spin_unlock_irqrestore
    10.34%      ksoftirqd/0  [kernel.kallsyms]  [k] __pi_memcpy
     9.83%      ksoftirqd/0  [kernel.kallsyms]  [k] ravb_poll
     7.89%      ksoftirqd/0  [kernel.kallsyms]  [k] skb_put
     4.01%      ksoftirqd/0  [kernel.kallsyms]  [k] dev_gro_receive
     3.37%          netperf  [kernel.kallsyms]  [k] __arch_copy_to_user
     3.17%          swapper  [kernel.kallsyms]  [k] arch_cpu_idle
     2.55%          swapper  [kernel.kallsyms]  [k] tick_nohz_idle_enter
     2.04%      ksoftirqd/0  [kernel.kallsyms]  [k] __pi___inval_dcache_area
     2.03%          swapper  [kernel.kallsyms]  [k] _raw_spin_unlock_irq
     1.96%      ksoftirqd/0  [kernel.kallsyms]  [k] __netdev_alloc_skb
     1.59%      ksoftirqd/0  [kernel.kallsyms]  [k] __slab_alloc.isra.83

Test results without RX checksum offload enabled:
 # /usr/bin/perf_3.16 record -o /run/perf.data -a netperf -t TCP_MAERTS -H 10.4.3.162
 MIGRATED TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.4.3.162 () port 0 AF_INET : demo
 enable_enobufs failed: getprotobyname
 Recv   Send    Send
 Socket Socket  Message  Elapsed
 Size   Size    Size     Time     Throughput
 bytes  bytes   bytes    secs.    10^6bits/sec

  87380  16384  16384    10.00     940.20

 Summary of output of perf report:
    17.10%    ksoftirqd/0  [kernel.kallsyms]  [k] _raw_spin_unlock_irqrestore
    10.99%    ksoftirqd/0  [kernel.kallsyms]  [k] __pi_memcpy
     8.87%    ksoftirqd/0  [kernel.kallsyms]  [k] ravb_poll
     8.16%    ksoftirqd/0  [kernel.kallsyms]  [k] skb_put
     7.42%    ksoftirqd/0  [kernel.kallsyms]  [k] do_csum
     3.91%    ksoftirqd/0  [kernel.kallsyms]  [k] dev_gro_receive
     2.31%        swapper  [kernel.kallsyms]  [k] arch_cpu_idle
     2.16%    ksoftirqd/0  [kernel.kallsyms]  [k] __pi___inval_dcache_area
     2.14%    ksoftirqd/0  [kernel.kallsyms]  [k] __netdev_alloc_skb
     1.93%        netperf  [kernel.kallsyms]  [k] __arch_copy_to_user
     1.79%        swapper  [kernel.kallsyms]  [k] tick_nohz_idle_enter
     1.63%    ksoftirqd/0  [kernel.kallsyms]  [k] __slab_alloc.isra.83

Above results collected on an R-Car Gen 3 Salvator-X/r8a7796 ES1.0.
Also tested on a R-Car Gen 3 Salvator-X/r8a7795 ES1.0.

By inspection this also appears to be compatible with the ravb found
on R-Car Gen 2 SoCs, however, this patch is currently untested on such
hardware.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-04 10:26:05 -07:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-09-23 10:16:53 -07:00
block block: directly insert blk-mq request from blk_insert_cloned_request() 2017-09-11 16:43:57 -06:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto crypto: af_alg - update correct dst SGL entry 2017-09-20 17:42:42 +08:00
Documentation net: Add support for networking over Thunderbolt cable 2017-10-02 11:24:42 -07:00
drivers ravb: RX checksum offload 2017-10-04 10:26:05 -07:00
firmware firmware: Restore support for built-in firmware 2017-09-16 10:58:48 -07:00
fs Various SMB3 fixes for stable and security improvements from the recently completed SMB3/Samba test events 2017-09-22 16:11:48 -10:00
include sctp: introduce round robin stream scheduler 2017-10-03 16:27:29 -07:00
init Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:54:01 -07:00
ipc ipc/shm: Fix order of parameters when calling copy_compat_shmid_to_user 2017-09-20 23:27:48 -04:00
kernel bpf: Fix compiler warning on info.map_ids for 32bit platform 2017-10-01 04:09:42 +01:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-09-23 10:16:53 -07:00
mm Merge branch 'work.read_write' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 19:29:55 -07:00
net sctp: introduce round robin stream scheduler 2017-10-03 16:27:29 -07:00
samples samples/bpf: fix warnings in xdp_monitor_user 2017-10-01 23:08:24 -07:00
scripts thunderbolt: Add support for XDomain discovery protocol 2017-10-02 11:24:41 -07:00
security + Features 2017-09-23 05:33:29 -10:00
sound vfs: constify path argument to kernel_read_file_from_path 2017-09-14 20:18:45 -07:00
tools selftests: rtnetlink.sh: add vxlan and fou test cases 2017-10-02 11:15:31 -07:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD" 2017-09-19 08:37:17 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS selinux/stable-4.14 PR 20170831 2017-09-12 13:21:00 -07:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS MAINTAINERS: Add entry for Thunderbolt network driver 2017-10-02 11:24:42 -07:00
Makefile Linux 4.14-rc1 2017-09-16 15:47:51 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
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See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
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