ipv6: reuse ip6_frag_id from ip6_ufo_append_data

commit 916e4cf46d0204806c062c8c6c4d1f633852c5b6 upstream.

Currently we generate a new fragmentation id on UFO segmentation. It
is pretty hairy to identify the correct net namespace and dst there.
Especially tunnels use IFF_XMIT_DST_RELEASE and thus have no skb_dst
available at all.

This causes unreliable or very predictable ipv6 fragmentation id
generation while segmentation.

Luckily we already have pregenerated the ip6_frag_id in
ip6_ufo_append_data and can use it here.

Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust filename, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Zefan Li <lizefan@huawei.com>
net: Do not enable tx-nocache-copy by default

commit cdb3f4a31b64c3a1c6eef40bc01ebc9594c58a8c upstream.

There are many cases where this feature does not improve performance or even
reduces it.

For example, here are the results from tests that I've run using 3.12.6 on one
Intel Xeon W3565 and one i7 920 connected by ixgbe adapters. The results are
from the Xeon, but they're similar on the i7. All numbers report the
mean±stddev over 10 runs of 10s.

1) latency tests similar to what is described in "c6e1a0d net: Allow no-cache
copy from user on transmit"
There is no statistically significant difference between tx-nocache-copy
on/off.
nic irqs spread out (one queue per cpu)

200x netperf -r 1400,1
tx-nocache-copy off
        692000±1000 tps
        50/90/95/99% latency (us): 275±2/643.8±0.4/799±1/2474.4±0.3
tx-nocache-copy on
        693000±1000 tps
        50/90/95/99% latency (us): 274±1/644.1±0.7/800±2/2474.5±0.7

200x netperf -r 14000,14000
tx-nocache-copy off
        86450±80 tps
        50/90/95/99% latency (us): 334.37±0.02/838±1/2100±20/3990±40
tx-nocache-copy on
        86110±60 tps
        50/90/95/99% latency (us): 334.28±0.01/837±2/2110±20/3990±20

2) single stream throughput tests
tx-nocache-copy leads to higher service demand

                        throughput  cpu0        cpu1        demand
                        (Gb/s)      (Gcycle)    (Gcycle)    (cycle/B)

nic irqs and netperf on cpu0 (1x netperf -T0,0 -t omni -- -d send)

tx-nocache-copy off     9402±5      9.4±0.2                 0.80±0.01
tx-nocache-copy on      9403±3      9.85±0.04               0.838±0.004

nic irqs on cpu0, netperf on cpu1 (1x netperf -T1,1 -t omni -- -d send)

tx-nocache-copy off     9401±5      5.83±0.03   5.0±0.1     0.923±0.007
tx-nocache-copy on      9404±2      5.74±0.03   5.523±0.009 0.958±0.002

As a second example, here are some results from Eric Dumazet with latest
net-next.
tx-nocache-copy also leads to higher service demand

(cpu is Intel(R) Xeon(R) CPU X5660  @ 2.80GHz)

lpq83:~# ./ethtool -K eth0 tx-nocache-copy on
lpq83:~# perf stat ./netperf -H lpq84 -c
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to lpq84.prod.google.com () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % U      us/KB   us/KB

 87380  16384  16384    10.00      9407.44   2.50     -1.00    0.522   -1.000

 Performance counter stats for './netperf -H lpq84 -c':

       4282.648396 task-clock                #    0.423 CPUs utilized
             9,348 context-switches          #    0.002 M/sec
                88 CPU-migrations            #    0.021 K/sec
               355 page-faults               #    0.083 K/sec
    11,812,797,651 cycles                    #    2.758 GHz                     [82.79%]
     9,020,522,817 stalled-cycles-frontend   #   76.36% frontend cycles idle    [82.54%]
     4,579,889,681 stalled-cycles-backend    #   38.77% backend  cycles idle    [67.33%]
     6,053,172,792 instructions              #    0.51  insns per cycle
                                             #    1.49  stalled cycles per insn [83.64%]
       597,275,583 branches                  #  139.464 M/sec                   [83.70%]
         8,960,541 branch-misses             #    1.50% of all branches         [83.65%]

      10.128990264 seconds time elapsed

lpq83:~# ./ethtool -K eth0 tx-nocache-copy off
lpq83:~# perf stat ./netperf -H lpq84 -c
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to lpq84.prod.google.com () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % U      us/KB   us/KB

 87380  16384  16384    10.00      9412.45   2.15     -1.00    0.449   -1.000

 Performance counter stats for './netperf -H lpq84 -c':

       2847.375441 task-clock                #    0.281 CPUs utilized
            11,632 context-switches          #    0.004 M/sec
                49 CPU-migrations            #    0.017 K/sec
               354 page-faults               #    0.124 K/sec
     7,646,889,749 cycles                    #    2.686 GHz                     [83.34%]
     6,115,050,032 stalled-cycles-frontend   #   79.97% frontend cycles idle    [83.31%]
     1,726,460,071 stalled-cycles-backend    #   22.58% backend  cycles idle    [66.55%]
     2,079,702,453 instructions              #    0.27  insns per cycle
                                             #    2.94  stalled cycles per insn [83.22%]
       363,773,213 branches                  #  127.757 M/sec                   [83.29%]
         4,242,732 branch-misses             #    1.17% of all branches         [83.51%]

      10.128449949 seconds time elapsed

CC: Tom Herbert <therbert@google.com>
Signed-off-by: Benjamin Poirier <bpoirier@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Zefan Li <lizefan@huawei.com>
ixgbevf: Prevent RX/TX statistics getting reset to zero

commit 936597631dd310e220544dc5c6075d924efd39b2 upstream.

The commit 4197aa7bb81877ebb06e4f2cc1b5fea2da23a7bd implements 64 bit
per ring statistics. But the driver resets the 'total_bytes' and
'total_packets' from RX and TX rings in the RX and TX interrupt
handlers to zero. This results in statistics being lost and user space
reporting RX and TX statistics as zero. This patch addresses the
issue by preventing the resetting of RX and TX ring statistics to
zero.

Signed-off-by: Narendra K <narendra_k@dell.com>
Tested-by: Sibai Li <sibai.li@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Weng Meiling <wengmeiling.weng@huawei.com>
Signed-off-by: Zefan Li <lizefan@huawei.com>