Re: e1000 latency problem or what ?

From: Oleksandr Samoylyk
Date: Mon Mar 03 2008 - 17:39:35 EST

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In reply to: Eric Dumazet: "Re: e1000 latency problem or what ?"
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Eric Dumazet wrote:

Kok, Auke a écrit :
Oleksandr Samoylyk wrote:
Dear community,

I'm running a busy pptp-server which serves about 1500 users on about 80
Mbit/s (> 15000 packets/sec) through it. I use poptop, traffic shaper
and basic firewall rules.

As for hardware it's a server on SuperMicro Server on X7DB8+ serverboard
server with 8 GB RAM on it running Ubuntu Server Edition.

As for problem, sometimes I get the following erors in logs:
Mar 3 15:21:14 vpn kernel: [ 0.000000] BUG: soft lockup - CPU#7
stuck for 11s! [events/7:34]
Mar 3 15:21:14 vpn kernel: [ 0.000000] CPU 7:
Mar 3 15:21:14 vpn kernel: [ 0.000000] Modules linked in: af_packet
xt_tcpmss iptable_mangle act_police sch_ingress cls_u32 sch_sfq sch_htb
e1000 xt_multiport xt_TCPMSS xt_state xt_limit xt_tcpudp
nf_conntrack_pptp nf_conntrack_proto_gre nf_nat_irc nf_conntrack_irc
nf_nat_ftp nf_conntrack_ftp iptable_nat nf_nat nf_conntrack_ipv4
nf_conntrack e1000e iptable_filter ip_tables x_tables tcp_cubic pptp
pppox ppp_generic slhc parport_pc lp parport loop iTCO_wdt
iTCO_vendor_support pcspkr shpchp i5000_edac pci_hotplug evdev edac_core
ext3 jbd mbcache sg sr_mod cdrom sd_mod ata_piix pata_acpi aic94xx
libsas ata_generic libata scsi_transport_sas scsi_mod fuse
Mar 3 15:21:14 vpn kernel: [ 0.000000] Pid: 34, comm: events/7 Not
tainted 2.6.24-11-server #1
Mar 3 15:21:14 vpn kernel: [ 0.000000] RIP:
0010:[libata:_spin_unlock_irqrestore+0x8/0x26222]
[libata:_spin_unlock_irqrestore+0x8/0x26222]
_spin_unlock_irqrestore+0x8/0x10
Mar 3 15:21:14 vpn kernel: [ 0.000000] RSP: 0018:ffff810225a779a0
EFLAGS: 00000246
Mar 3 15:21:14 vpn kernel: [ 0.000000] RAX: 0000000000000000 RBX:
ffffc20001a1ab80 RCX: 0000000000000000
Mar 3 15:21:14 vpn kernel: [ 0.000000] RDX: 0000000000000014 RSI:
0000000000000246 RDI: ffff8102249d5aa8
Mar 3 15:21:14 vpn kernel: [ 0.000000] RBP: ffff810225a77920 R08:
0000000000001000 R09: 0000000002000000
Mar 3 15:21:14 vpn kernel: [ 0.000000] R10: 0000000000000000 R11:
ffff81021ac01300 R12: ffffffff8020cfb6
Mar 3 15:21:14 vpn kernel: [ 0.000000] R13: 0000000000000000 R14:
ffff8102249d5a80 R15: 0000000000000010
Mar 3 15:21:14 vpn kernel: [ 0.000000] FS: 0000000000000000(0000)
GS:ffff81022590cd00(0000) knlGS:0000000000000000
Mar 3 15:21:14 vpn kernel: [ 0.000000] CS: 0010 DS: 0018 ES: 0018
CR0: 000000008005003b
Mar 3 15:21:14 vpn kernel: [ 0.000000] CR2: 00007fa2778f7315 CR3:
0000000000201000 CR4: 00000000000006e0
Mar 3 15:21:14 vpn kernel: [ 0.000000] DR0: 0000000000000000 DR1:
0000000000000000 DR2: 0000000000000000
Mar 3 15:21:14 vpn kernel: [ 0.000000] DR3: 0000000000000000 DR6:
00000000ffff0ff0 DR7: 0000000000000400
Mar 3 15:21:14 vpn kernel: [ 0.000000]
Mar 3 15:21:14 vpn kernel: [ 0.000000] Call Trace:
Mar 3 15:21:14 vpn kernel: [ 0.000000] <IRQ> [<ffffffff8825ab1c>]
:e1000:e1000_xmit_frame+0x8fc/0xcb0
Mar 3 15:21:14 vpn kernel: [ 0.000000]
[e1000:____versions+0x56f3/0x7340]
:nf_conntrack_ipv4:ipv4_confirm+0x33/0x60
Mar 3 15:21:14 vpn kernel: [ 0.000000]
[dev_hard_start_xmit+0x22c/0x2a0] dev_hard_start_xmit+0x22c/0x2a0
Mar 3 15:21:14 vpn kernel: [ 0.000000] [__qdisc_run+0x74/0x1f0]
__qdisc_run+0x74/0x1f0
Mar 3 15:21:14 vpn kernel: [ 0.000000] [dev_queue_xmit+0x1e8/0x300]
dev_queue_xmit+0x1e8/0x300
Mar 3 15:21:14 vpn kernel: [ 0.000000] [pptp:pptp_xmit+0x567/0x7e0]
:pptp:pptp_xmit+0x567/0x7e0
Mar 3 15:21:14 vpn kernel: [ 0.000000]
[ppp_generic:ppp_push+0x45c/0x620] :ppp_generic:ppp_push+0x45c/0x620
Mar 3 15:21:14 vpn kernel: [ 0.000000] [<ffffffff8827b235>]
:sch_htb:htb_safe_rb_erase+0x15/0x50
Mar 3 15:21:14 vpn kernel: [ 0.000000] [<ffffffff8827b635>]
:sch_htb:htb_deactivate_prios+0x1a5/0x250
Mar 3 15:21:14 vpn kernel: [ 0.000000]
[ppp_generic:ppp_xmit_process+0x469/0x640]
:ppp_generic:ppp_xmit_process+0x469/0x640
Mar 3 15:21:14 vpn kernel: [ 0.000000]
[ppp_generic:ppp_start_xmit+0x151/0x1e0]
:ppp_generic:ppp_start_xmit+0x151/0x1e0
Mar 3 15:21:14 vpn kernel: [ 0.000000]
[dev_hard_start_xmit+0x22c/0x2a0] dev_hard_start_xmit+0x22c/0x2a0
Mar 3 15:21:14 vpn kernel: [ 0.000000] [__qdisc_run+0x74/0x1f0]
__qdisc_run+0x74/0x1f0
Mar 3 15:21:14 vpn kernel: [ 0.000000] [dev_queue_xmit+0x1e8/0x300]
dev_queue_xmit+0x1e8/0x300
Mar 3 15:21:14 vpn kernel: [ 0.000000] [ip_rcv_finish+0x114/0x3b0]
ip_rcv_finish+0x114/0x3b0
Mar 3 15:21:14 vpn kernel: [ 0.000000] [ip_rcv+0x212/0x300]
ip_rcv+0x212/0x300
Mar 3 15:21:14 vpn kernel: [ 0.000000]
[e1000:netif_receive_skb+0x3ac/0xd80] netif_receive_skb+0x3ac/0x490
Mar 3 15:21:14 vpn kernel: [ 0.000000] [<ffffffff8825c7a4>]
:e1000:e1000_clean_rx_irq+0x1c4/0x590
Mar 3 15:21:14 vpn kernel: [ 0.000000] [<ffffffff88259609>]
:e1000:e1000_clean+0x69/0x250
Mar 3 15:21:14 vpn kernel: [ 0.000000] [net_rx_action+0x128/0x230]
net_rx_action+0x128/0x230
Mar 3 15:21:14 vpn kernel: [ 0.000000] [__do_softirq+0x75/0xe0]
__do_softirq+0x75/0xe0
Mar 3 15:21:14 vpn kernel: [ 0.000000] [call_softirq+0x1c/0x30]
call_softirq+0x1c/0x30
Mar 3 15:21:14 vpn kernel: [ 0.000000] <EOI>
[pptp:_ack_timeout_work+0x0/0x20] :pptp:_ack_timeout_work+0x0/0x20
Mar 3 15:21:14 vpn kernel: [ 0.000000] [do_softirq+0x35/0x90]
do_softirq+0x35/0x90
Mar 3 15:21:14 vpn kernel: [ 0.000000]
[local_bh_enable_ip+0x54/0x60] local_bh_enable_ip+0x54/0x60
Mar 3 15:21:14 vpn kernel: [ 0.000000] [run_workqueue+0xcc/0x170]
run_workqueue+0xcc/0x170
Mar 3 15:21:14 vpn kernel: [ 0.000000] [worker_thread+0x0/0x110]
worker_thread+0x0/0x110
Mar 3 15:21:14 vpn kernel: [ 0.000000] [worker_thread+0x0/0x110]
worker_thread+0x0/0x110
Mar 3 15:21:14 vpn kernel: [ 0.000000] [worker_thread+0xa3/0x110]
worker_thread+0xa3/0x110
Mar 3 15:21:14 vpn kernel: [ 0.000000] [<ffffffff802543d0>]
autoremove_wake_function+0x0/0x30
Mar 3 15:21:14 vpn kernel: [ 0.000000] [worker_thread+0x0/0x110]
worker_thread+0x0/0x110
Mar 3 15:21:14 vpn kernel: [ 0.000000] [worker_thread+0x0/0x110]
worker_thread+0x0/0x110
Mar 3 15:21:14 vpn kernel: [ 0.000000] [kthread+0x4b/0x80]
kthread+0x4b/0x80
Mar 3 15:21:14 vpn kernel: [ 0.000000] [child_rip+0xa/0x12]
child_rip+0xa/0x12
Mar 3 15:21:14 vpn kernel: [ 0.000000] [kthread+0x0/0x80]
kthread+0x0/0x80
Mar 3 15:21:14 vpn kernel: [ 0.000000] [child_rip+0x0/0x12]
child_rip+0x0/0x12
Mar 3 15:21:14 vpn kernel: [ 0.000000]

One of my CPUs goes 100% with ksoftirqd.

sysreq-t?

Latency increases signifcantly during this this (more than >100ms).

ethtool -G eth0 tx 4096 rx 4096
ethtool -G eth1 tx 4096 rx 4096

unless you're not seeing rx_no_buffer_count increase in the `ethtool -S ethx`
increase this is unnecesary

echo "8192" > /proc/sys/vm/min_free_kbytes

ditto

I attached IRQ to different CPUs by:
/bin/echo "0f" > /proc/irq/2297/smp_affinity
/bin/echo "f0" > /proc/irq/2296/smp_affinity

root@vpn:~# cat /proc/interrupts
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5
CPU6 CPU7
0: 72 0 0 0 0 0
0 0 XT-PIC-XT timer
1: 2 0 0 0 0 0
0 0 XT-PIC-XT i8042
2: 0 0 0 0 0 0
0 0 XT-PIC-XT cascade
8: 1 0 0 0 0 0
0 0 XT-PIC-XT rtc
11: 9117 0 0 0 0 0
0 0 XT-PIC-XT aic94xx
14: 84 0 0 0 0 0
0 0 XT-PIC-XT libata
15: 0 0 0 0 0 0
0 0 XT-PIC-XT libata
2296: 76853 76976 76639 76692 248073 247957
248079 248084 PCI-MSI-edge eth1
2297: 266795 266672 267009 266956 93920 94035
93914 93908 PCI-MSI-edge eth0

your cpu is round-robinning network interrupts which is bad, turn the in-kernel
irqbalance feature OFF and use the userspace irqbalance tool instead

ifconfig eth0 txqueuelen 1000
ifconfig eth1 txqueuelen 1000

I wanted to switch to e1000e driver instead of e1000 as I've in kernel:

CONFIG_E1000=m
CONFIG_E1000E=m
# CONFIG_E1000_DISABLE_PACKET_SPLIT is not set
CONFIG_E1000_NAPI=y

I'm trying to load it by:
modprobe -r e1000; modprobe e1000e; /etc/init.d/networking restart

but NICs aren't detected :(

Why so?

because that device is not going to be supported by e1000e until 2.6.25. you're
using 2.6.24 so you need to use e1000 just one kernel release longer.

I have (lspci -vvv output):

06:00.0 Ethernet controller: Intel Corporation 80003ES2LAN Gigabit
Ethernet Controller (Copper) (rev 01)
Subsystem: Super Micro Computer Inc Unknown device 0000
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
ParErr+ Stepping- SERR+ FastB2B-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
Latency: 0, Cache Line Size: 32 bytes
Interrupt: pin A routed to IRQ 2297
Region 0: Memory at d8300000 (32-bit, non-prefetchable) [size=128K]
Region 2: I/O ports at 3000 [size=32]
Capabilities: [c8] Power Management version 2
Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA
PME(D0+,D1-,D2-,D3hot+,D3cold+)
Status: D0 PME-Enable- DSel=0 DScale=1 PME-
Capabilities: [d0] Message Signalled Interrupts: Mask- 64bit+
Queue=0/0 Enable+
Address: 00000000fee0f00c Data: 41b9
Capabilities: [e0] Express Endpoint IRQ 0
Device: Supported: MaxPayload 256 bytes, PhantFunc 0,
ExtTag-
Device: Latency L0s <512ns, L1 <64us
Device: AtnBtn- AtnInd- PwrInd-
Device: Errors: Correctable- Non-Fatal- Fatal- Unsupported-
Device: RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
Device: MaxPayload 128 bytes, MaxReadReq 512 bytes
Link: Supported Speed 2.5Gb/s, Width x4, ASPM unknown,
Port 0
Link: Latency L0s <128ns, L1 <64us
Link: ASPM Disabled RCB 64 bytes CommClk- ExtSynch-
Link: Speed 2.5Gb/s, Width x4

06:00.1 Ethernet controller: Intel Corporation 80003ES2LAN Gigabit
Ethernet Controller (Copper) (rev 01)
Subsystem: Super Micro Computer Inc Unknown device 0000
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
ParErr+ Stepping- SERR+ FastB2B-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
Latency: 0, Cache Line Size: 32 bytes
Interrupt: pin B routed to IRQ 2296
Region 0: Memory at d8320000 (32-bit, non-prefetchable) [size=128K]
Region 2: I/O ports at 3020 [size=32]
Capabilities: [c8] Power Management version 2
Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA
PME(D0+,D1-,D2-,D3hot+,D3cold+)
Status: D0 PME-Enable- DSel=0 DScale=1 PME-
Capabilities: [d0] Message Signalled Interrupts: Mask- 64bit+
Queue=0/0 Enable+
Address: 00000000feef000c Data: 41c1
Capabilities: [e0] Express Endpoint IRQ 0
Device: Supported: MaxPayload 256 bytes, PhantFunc 0,
ExtTag-
Device: Latency L0s <512ns, L1 <64us
Device: AtnBtn- AtnInd- PwrInd-
Device: Errors: Correctable- Non-Fatal- Fatal- Unsupported-
Device: RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
Device: MaxPayload 128 bytes, MaxReadReq 512 bytes
Link: Supported Speed 2.5Gb/s, Width x4, ASPM unknown,
Port 0
Link: Latency L0s <128ns, L1 <64us
Link: ASPM Disabled RCB 64 bytes CommClk- ExtSynch-
Link: Speed 2.5Gb/s, Width x4

So I still have to use e1000 with InterruptThrottleRate=0,0
RxIntDelay=0,0 RxAbsIntDelay=0,0 TxIntDelay=0,0 TxAbsIntDelay=0,0:

just use the defaults for e1000 please, unless those defaults don't work - and
then it's a bug.

I don't think e1000 is the issue here, I've definately not seen any reports of
e1000+pptp giving issues. perhaps one of the pptp/pppd developers can look at the
stack trace.

I cant find pptp_xmit() function in 2.6.24 sources. I must be blind, or some contextual information is missing.

My fault. Besides, I use http://sourceforge.net/projects/accel-pptp/

#define PPTP_DRIVER_VERSION "0.7.12"

MODULE_DESCRIPTION("Point-to-Point Tunneling Protocol for Linux");
MODULE_AUTHOR("Kozlov D. (xeb@xxxxxxx)");
MODULE_LICENSE("GPL");

--
Oleksandr Samoylyk
OVS-RIPE
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Next message: Andrew Morton: "Re: [PATCH][2.6.25-rc2-mm1] fix a null pointer bug inregister_kretprobe"
Previous message: Christian Kujau: "Re: WARNING: at drivers/usb/host/ehci-hcd.c:287"
In reply to: Eric Dumazet: "Re: e1000 latency problem or what ?"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]