Re: Re: limited network bandwidth with 3.2.x kernels

alekcejk
2012-02-13T21:17:11Z

В сообщении от Понедельник 13 февраля 2012 21:18:13 вы написали:
> Le lundi 13 février 2012 à 22:04 +0200, alekcejk@googlemail.com a
>
> écrit :
> > Hi,
> >
> > I noticed that with 3.2.x kernels download speed from some internet resources
> > became about half of speed that was with previous kernels (3.1 and older).
> > I tested Fedora 15 kernels 2.6.41.10 = 3.1.10 and 2.6.42.3 = 3.2.3
> > (many times rebooted for testing with first and second kernels).
> > See bug https://bugzilla.redhat.com/show_bug.cgi?id=789659
> >
> > lsmod:
> > Module Size Used by
> > nvidia 10778232 40
> > i2c_core 28123 1 nvidia
> > 8139too 32490 0
> > mii 13311 1 8139too
> >
> > dmesg:
> > 8139too: 8139too Fast Ethernet driver 0.9.28
> > 8139too 0000:01:02.0: PCI INT A -> GSI 22 (level, low) -> IRQ 22
> > 8139too 0000:01:02.0: eth0: RealTek RTL8139 at , IRQ 22
> > 8139too 0000:01:02.0: eth0: link up, 100Mbps, full-duplex, lpa 0x41E1
> >
> > For testing I selected fastest for me download mirrors of FreeBSD and Ubuntu,
> > also I tested download speed from site speedtest.tele2.net.
> >
> > For these sites download speed with 3.1 kernels (and older) is about 11 MB/s
> > but with 3.2.x kernels - limited 5.5 MB/s and for some sites still approximately
> > the same as with 3.1 kernels (see bug mentioned above).
>
> MB/s means MBytes or Mbits ?

MB means MegaBytes. This should explain it:

FreeBSD-8.2-RELEASE-i386-dvd1.iso.xz size 2066424512 bytes (1.9 G) downloaded with both kernels:

kernel 3.1.10: saved in 3m 31s 9,32 Megabytes/second - average speed, 11,1 Megabytes/second maximum
kernel 3.2.3: saved in 5m 56s 5,54 Megabytes/second - average speed, 5,64 Megabytes/s - maximum speed

>
> > Also I want to pay attention that limited speed stays constant - always
> > 5.5 MB/s with straight line on traffic plotter as if was network bandwidth shaping.
> > With 3.1 kernels this never happens - speed can vary in some ranges
> > but at maximum it is about 11 MB/s, no limitations such as 5.5 MB/s.
>
> Could you post "netstat -s" result ?

"netstat -s" just after system started and download finished

kernel 3.1.10:

Ip:
1472431 total packets received
0 forwarded
0 incoming packets discarded
1469765 incoming packets delivered
755430 requests sent out
1 outgoing packets dropped
Icmp:
0 ICMP messages received
0 input ICMP message failed.
ICMP input histogram:
1 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
echo request: 1
IcmpMsg:
OutType8: 1
Tcp:
4 active connections openings
0 passive connection openings
0 failed connection attempts
0 connection resets received
0 connections established
1469723 segments received
755378 segments send out
0 segments retransmited
0 bad segments received.
32997 resets sent
Udp:
35 packets received
0 packets to unknown port received.
0 packet receive errors
52 packets sent
0 receive buffer errors
0 send buffer errors
UdpLite:
TcpExt:
1 TCP sockets finished time wait in fast timer
22 delayed acks sent
1448 packets directly received from backlog
1429173 packets header predicted
1 packets header predicted and directly queued to user
2 acknowledgments not containing data received
18 predicted acknowledgments
0 TCP data loss events
1 connections reset due to unexpected data
IPReversePathFilter: 47
IpExt:
InNoRoutes: 218
InMcastPkts: 2
InBcastPkts: 46
OutBcastPkts: 17
InOctets: 2157119711
OutOctets: 38981662
InMcastOctets: 56
InBcastOctets: 3704
OutBcastOctets: 768

kernel 3.2.3:

Ip:
1487136 total packets received
0 forwarded
0 incoming packets discarded
1482687 incoming packets delivered
769964 requests sent out
1 outgoing packets dropped
Icmp:
0 ICMP messages received
0 input ICMP message failed.
ICMP input histogram:
1 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
echo request: 1
IcmpMsg:
OutType8: 1
Tcp:
2 active connections openings
0 passive connection openings
0 failed connection attempts
0 connection resets received
0 connections established
1482636 segments received
769905 segments send out
0 segments retransmited
0 bad segments received.
55530 resets sent
Udp:
42 packets received
0 packets to unknown port received.
0 packet receive errors
59 packets sent
0 receive buffer errors
0 send buffer errors
UdpLite:
TcpExt:
1 TCP sockets finished time wait in fast timer
15 delayed acks sent
1425598 packets header predicted
1 acknowledgments not containing data received
9 predicted acknowledgments
0 TCP data loss events
IPReversePathFilter: 48
IpExt:
InNoRoutes: 235
InMcastPkts: 4
InBcastPkts: 47
OutBcastPkts: 17
InOctets: 2143692697
OutOctets: 39392421
InMcastOctets: 112
InBcastOctets: 3941
OutBcastOctets: 768