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Date:      Sat, 03 May 2008 23:29:50 +0300
From:      Oleksandr Samoylyk <oleksandr@samoylyk.sumy.ua>
To:        freebsd-net@freebsd.org
Subject:   Troubles with em on FreeBSD 7
Message-ID:  <481CCB3E.9070302@samoylyk.sumy.ua>

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Hi!

I'm running a SMP FreeBSD box with mpd5 on it.

# uname -a
FreeBSD xxx.xxxxxxxxx.xxx 7.0-STABLE FreeBSD 7.0-STABLE #0: Sat May  3 
12:40:02 EEST 2008     xxxxx@xxx.xxxxxxxxx.xxx:/usr/obj/usr/src/sys/XXXX 
  amd64

# mpd5 -v
Version 5.1 (root@xxx.xxxxxxxxx.xxx 09:53  1-May-2008)

Somehow em0 begins to eat all CPU time of one core.

# top -S
last pid: 55827;  load averages:  3.76,  3.42,  3.08 
                         up 0+03:27:38  16:24:20
104 processes: 11 running, 81 sleeping, 12 waiting
CPU states:  1.7% user,  0.0% nice, 21.4% system,  3.0% interrupt, 73.9% 
idle
Mem: 71M Active, 89M Inact, 340M Wired, 336K Cache, 214M Buf, 7418M Free
Swap: 4096M Total, 4096M Free

   PID USERNAME  THR PRI NICE   SIZE    RES STATE  C   TIME   WCPU COMMAND
    29 root        1 -68    -     0K    16K CPU5   5 196:41 100.00% em0 
taskq
    11 root        1 171 ki31     0K    16K CPU7   7 175:41 94.09% idle: 
cpu7
    16 root        1 171 ki31     0K    16K CPU2   2 175:45 91.26% idle: 
cpu2
    15 root        1 171 ki31     0K    16K CPU3   3 180:18 89.45% idle: 
cpu3
    14 root        1 171 ki31     0K    16K CPU4   4 177:13 87.89% idle: 
cpu4
    17 root        1 171 ki31     0K    16K CPU1   1 165:27 86.87% idle: 
cpu1
    12 root        1 171 ki31     0K    16K CPU6   6 176:18 83.25% idle: 
cpu6
    18 root        1 171 ki31     0K    16K RUN    0 157:44 80.66% idle: 
cpu0
   611 root        6  58    0   133M 44320K select 0   0:00 66.26% mpd5
    21 root        1 -44    -     0K    16K CPU4   4  48:38 21.39% swi1: net
    30 root        1 -68    -     0K    16K -      6  21:41 10.25% em1 taskq

Everything is OK with outbound interface - em1.

Current bandwidth - ~ 80 Mbit/s

There are a lot of input errors on em0 (but no on em1):

# netstat -w 1 -I em0
             input          (em0)           output
    packets  errs      bytes    packets  errs      bytes colls
       8012   923    2838565      12504     0    7943345     0
       7934   874    2469244      12555     0    7728764     0
       7931   976    2712035      12482     0    8006760     0
       8015   813    2694716      10669     0    7796656     0
       7975   733    2475193      12306     0    8032129     0
       7871   825    2548198      12269     0    7789452     0
       8072   961    2647014      11924     0    7260788     0
       7909   983    2576145      10552     0    7479881     0
^C

And systat -v looks strange with no interrupts on em0:

     2 users    Load  1.34  1.61  1.62                  May  3 14:04

Mem:KB    REAL            VIRTUAL                       VN PAGER   SWAP 
PAGER
         Tot   Share      Tot    Share    Free           in   out     in 
   out
Act   68152    9452   231584    11936 7786368  count
All  108516   10676  4486380    15448          pages
Proc:                                                            Interrupts
   r   p   d   s   w   Csw  Trp  Sys  Int  Sof  Flt   3981 cow   22705 total
              47       46k  10k 268k 6697  23k  10k   3973 zfod atkbd0 1
                                                           ozfod ata0 irq14
18.3%Sys   2.3%Intr  1.8%User  0.0%Nice 77.6%Idle        %ozfod atapci1 19
|    |    |    |    |    |    |    |    |    |    |       daefr  2001 
cpu0: time
=========+>                                          5699 prcfr     2 
em0 irq256
                                         55 dtbuf    12110 totfr  6695 
em1 irq257
Namei     Name-cache   Dir-cache    100000 desvn          react  2001 
cpu3: time
    Calls    hits   %    hits   %      4217 numvn          pdwak  2001 
cpu1: time
    12005   12004 100                   304 frevn          pdpgs  2001 
cpu2: time
                                                        13 intrn  2001 
cpu4: time
Disks   ad4                                        232692 wire   2001 
cpu5: time
KB/t   0.00                                         60640 act    2001 
cpu7: time
tps       0                                         28784 inact  2001 
cpu6: time
MB/s   0.00                                           336 cache
%busy     0                                       7786032 free
                                                    219632 buf

Latency grows up to 400 ms:
# ping 10.0.0.1
PING 10.0.0.1 (10.0.0.1): 56 data bytes
64 bytes from 10.0.0.1: icmp_seq=0 ttl=64 time=17.619 ms
64 bytes from 10.0.0.1: icmp_seq=1 ttl=64 time=27.497 ms
64 bytes from 10.0.0.1: icmp_seq=3 ttl=64 time=16.481 ms
64 bytes from 10.0.0.1: icmp_seq=4 ttl=64 time=24.535 ms
64 bytes from 10.0.0.1: icmp_seq=5 ttl=64 time=13.058 ms
^C
--- 10.0.0.1 ping statistics ---
6 packets transmitted, 5 packets received, 16.7% packet loss
round-trip min/avg/max/stddev = 13.058/19.838/27.497/5.346 ms

# top -S
last pid: 55827;  load averages:  3.76,  3.42,  3.08 
                         up 0+03:27:38  16:24:20
104 processes: 11 running, 81 sleeping, 12 waiting
CPU states:  1.7% user,  0.0% nice, 21.4% system,  3.0% interrupt, 73.9% 
idle
Mem: 71M Active, 89M Inact, 340M Wired, 336K Cache, 214M Buf, 7418M Free
Swap: 4096M Total, 4096M Free

   PID USERNAME  THR PRI NICE   SIZE    RES STATE  C   TIME   WCPU COMMAND
    29 root        1 -68    -     0K    16K CPU5   5 196:41 100.00% em0 
taskq
    11 root        1 171 ki31     0K    16K CPU7   7 175:41 94.09% idle: 
cpu7
    16 root        1 171 ki31     0K    16K CPU2   2 175:45 91.26% idle: 
cpu2
    15 root        1 171 ki31     0K    16K CPU3   3 180:18 89.45% idle: 
cpu3
    14 root        1 171 ki31     0K    16K CPU4   4 177:13 87.89% idle: 
cpu4
    17 root        1 171 ki31     0K    16K CPU1   1 165:27 86.87% idle: 
cpu1
    12 root        1 171 ki31     0K    16K CPU6   6 176:18 83.25% idle: 
cpu6
    18 root        1 171 ki31     0K    16K RUN    0 157:44 80.66% idle: 
cpu0
   611 root        6  58    0   133M 44320K select 0   0:00 66.26% mpd5
    21 root        1 -44    -     0K    16K CPU4   4  48:38 21.39% swi1: net
    30 root        1 -68    -     0K    16K -      6  21:41 10.25% em1 taskq

# sysctl dev.em.0
dev.em.0.%desc: Intel(R) PRO/1000 Network Connection Version - 6.7.3
dev.em.0.%driver: em
dev.em.0.%location: slot=0 function=0
dev.em.0.%pnpinfo: vendor=0x8086 device=0x1096 subvendor=0x15d9 
subdevice=0x0000 class=0x020000
dev.em.0.%parent: pci6
dev.em.0.debug: -1
dev.em.0.stats: -1
dev.em.0.rx_int_delay: 0
dev.em.0.tx_int_delay: 66
dev.em.0.rx_abs_int_delay: 66
dev.em.0.tx_abs_int_delay: 66
dev.em.0.rx_processing_limit: -1

I've tried both:
options         SCHED_ULE
options         SCHED_4BSD

I've added just the following lines in my kernel config:

options         IPFIREWALL
options         IPFIREWALL_DEFAULT_TO_ACCEPT

options         NETGRAPH
options         NETGRAPH_PPP
options         NETGRAPH_PPTPGRE


My sysctls:
  net.inet.ip.forwarding=1
net.inet.ip.fastforwarding=1
net.inet.ip.redirect=0
net.inet.ip.random_id=1
net.inet.ip.ttl=255
net.inet.ip.intr_queue_maxlen=4096

kern.maxfiles=131072
kern.maxfilesperproc=32768
kern.maxprocperuid=32768

kern.ipc.somaxconn=65535
kern.ipc.maxsockets=32768
kern.ipc.maxsockbuf=16777216

net.inet.tcp.rfc1323=1
net.inet.tcp.recvspace=65536
net.inet.tcp.sendspace=32768
net.inet.tcp.sendbuf_max=16777216
net.inet.tcp.recvbuf_max=16777216
net.inet.tcp.sendbuf_auto=1
net.inet.tcp.sendbuf_inc=8192
net.inet.tcp.recvbuf_auto=1
net.inet.tcp.recvbuf_inc=16384
net.inet.tcp.maxtcptw=40960
net.inet.tcp.msl=2500
net.inet.tcp.delayed_ack=0
net.inet.tcp.nolocaltimewait=1

net.inet.udp.checksum=0
net.inet.udp.recvspace=65535
net.inet.udp.maxdgram=57344

net.inet.icmp.icmplim=30

net.inet.tcp.blackhole=2
net.inet.udp.blackhole=1

net.local.stream.recvspace=65535
net.local.stream.sendspace=65535

net.isr.direct=1

kern.timecounter.hardware=TSC

dev.em.0.rx_processing_limit=-1

If I set net.isr.direct to "0", than sw1: net begins to eat 100% of a 
core, but without errors:
# netstat -w 1 -I em0
             input          (em0)           output
    packets  errs      bytes    packets  errs      bytes colls
       6953     0    2860537       8703     0    4882814     0
       6785     0    2587635       7683     0    4443958     0
       7006     0    2576630       8718     0    4924591     0
       6887     0    2652461       8272     0    4548049     0
       6854     0    2610157       8689     0    5152459     0
       6889     0    2586067       8265     0    5010795     0
       6878     0    2586746       8255     0    4734959     0
^C

Moreover, with net.isr.direct=0 I can't create a PPTP tunnel.

Please, help to solve the problem. Thanks!

-- 
  Oleksandr Samoylyk
  OVS-RIPE



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