Re: [PATCH] af_packet: Don't use skb after dev_queue_xmit()

From: Michael Breuer
Date: Thu Jan 07 2010 - 00:55:21 EST

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On 1/7/2010 12:32 AM, Michael Breuer wrote:

On 1/6/2010 11:53 PM, Stephen Hemminger wrote:
On Wed, 06 Jan 2010 23:00:34 -0500
Michael Breuer<mbreuer@xxxxxxxxxx> wrote:

Changing MTU to 9000, everything basically breaks - Can't use X11 (local
or remote - get X11 screen after gdm login locally, but then goes back
to greeter; remote gets no greeter); ssh sessions hang; etc. This time I
was able to reset the MTU back to 1500 without a reboot - but I did have
to ifconfig eth0 down and then up. Looking at the sk98lin code, it looks
to me like they do a bit more work with existing buffers before
completing the MTU switch. Note that even doing this, X11 did not work
(it did with the old mtu change code). Tried changing to mtu 4500 - same
effect as 9000... but when I switched back to 1500, ksoftirqd started
spinning using 100% of one core.
The problem is that patch was enabling scatter-gather and checksum offload
that won't work on EC_U hardware with 9K MTU. At least, it never worked
for me when I tested it. So because of that it really doesn't change anything
for the better on that chip version.

What version chip is on that motherboard? Mine is:
Yukon-2 EC Ultra chip revision 3
which corresponds to B0 step.

Another possibility is the PHY register which controls number of ticks
of buffering. The default is zero, which gives the most buffering (good),
but the firmware could be reprogramming it (bad). In general, the driver
doesn't fiddle with bits that are already set correctly, because sometimes
vendors need to tweak PCI timing in firmware/BIOS. It seems the firmware on this
chip is just a bunch of register setups done on power on.
Also - I'm seeing a huge number of dropped packets (RX) 200-300/second. Probably why this is so slow.

Current ifconfig:
eth0 Link encap:Ethernet HWaddr 00:26:18:00:1C:3B
inet addr:10.0.0.1 Bcast:10.0.0.255 Mask:255.255.255.0
inet6 addr: fe80::226:18ff:fe00:1c3b/64 Scope:Link
UP BROADCAST RUNNING ALLMULTI MULTICAST MTU:1500 Metric:1
RX packets:26647536 errors:0 dropped:517884 overruns:0 frame:0
TX packets:12112780 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:38960063319 (36.2 GiB) TX bytes:1889879762 (1.7 GiB)
Interrupt:18

Never mind... spoke too soon. Crashed again. Just took longer:
Jan 7 00:37:39 mail kernel: DRHD: handling fault status reg 2
Jan 7 00:37:39 mail kernel: DMAR:[DMA Read] Request device [06:00.0] fault addr fff1401fe000
Jan 7 00:37:39 mail kernel: DMAR:[fault reason 06] PTE Read access is not set
Jan 7 00:37:39 mail kernel: sky2 0000:06:00.0: error interrupt status=0x80000000
Jan 7 00:37:39 mail kernel: sky2 0000:06:00.0: PCI hardware error (0x2010)
Jan 7 00:37:40 mail smbd[4729]: [2010/01/07 00:37:40, 0] lib/util_sock.c:539(read_fd_with_timeout)
Jan 7 00:37:40 mail smbd[4729]: [2010/01/07 00:37:40, 0] lib/util_sock.c:1491(get_peer_addr_internal)
Jan 7 00:37:40 mail smbd[4729]: getpeername failed. Error was Transport endpoint is not connected
Jan 7 00:37:40 mail smbd[4729]: read_fd_with_timeout: client 0.0.0.0 read error = Connection timed out.
Jan 7 00:37:40 mail dhcpd: DHCPREQUEST for 10.0.0.32 from 00:26:bb:aa:15:10 (mbitouch) via eth0
Jan 7 00:37:40 mail dhcpd: DHCPACK on 10.0.0.32 to 00:26:bb:aa:15:10 (mbitouch) via eth0
Jan 7 00:37:41 mail dhcpd: DHCPREQUEST for 10.0.0.32 from 00:26:bb:aa:15:10 (mbitouch) via eth0
Jan 7 00:37:41 mail dhcpd: DHCPACK on 10.0.0.32 to 00:26:bb:aa:15:10 (mbitouch) via eth0
Jan 7 00:37:44 mail dhcpd: DHCPREQUEST for 10.0.0.32 from 00:26:bb:aa:15:10 (mbitouch) via eth0
Jan 7 00:37:44 mail dhcpd: DHCPACK on 10.0.0.32 to 00:26:bb:aa:15:10 (mbitouch) via eth0
Jan 7 00:37:47 mail kernel: ------------[ cut here ]------------
Jan 7 00:37:47 mail kernel: WARNING: at net/sched/sch_generic.c:261 dev_watchdog+0xf3/0x164()
Jan 7 00:37:47 mail kernel: Hardware name: System Product Name
Jan 7 00:37:47 mail kernel: NETDEV WATCHDOG: eth0 (sky2): transmit queue 0 timed out
Jan 7 00:37:47 mail kernel: Modules linked in: ip6table_filter ip6table_mangle ip6_tables ipt_MASQUERADE iptable_nat nf_nat iptable_mangle iptable_raw bridge stp appletalk psnap llc nfsd lockd nfs_acl auth_rpcgss exportfs hwmon_vid coretemp sunrpc acpi_cpufreq sit tunnel4 ipt_LOG nf_conntrack_netbios_ns nf_conntrack_ftp xt_DSCP xt_dscp xt_MARK nf_conntrack_ipv6 xt_multiport ipv6 dm_multipath kvm_intel kvm snd_hda_codec_analog snd_hda_intel snd_hda_codec snd_ens1371 gameport snd_rawmidi gspca_spca505 gspca_main pcspkr snd_ac97_codec snd_hwdep i2c_i801 snd_seq firewire_ohci videodev v4l1_compat snd_seq_device v4l2_compat_ioctl32 ac97_bus firewire_core crc_itu_t iTCO_wdt snd_pcm iTCO_vendor_support wmi snd_timer snd sky2 asus_atk0110 hwmon soundcore snd_page_alloc fbcon tileblit font bitblit softcursor raid456 async_raid6_recov async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 ata_generic pata_acpi pata_marvell nouveau ttm drm_kms_helper drm agpgart fb i2c_algo_bit cfbcopyarea i2c_core cfbimgblt cfbfil
Jan 7 00:37:47 mail kernel: lrect [last unloaded: microcode]
Jan 7 00:37:47 mail kernel: Pid: 0, comm: swapper Tainted: G W 2.6.32-00840-gec8257c-dirty #44
Jan 7 00:37:47 mail kernel: Call Trace:
Jan 7 00:37:47 mail kernel: <IRQ> [<ffffffff8105365a>] warn_slowpath_common+0x7c/0x94
Jan 7 00:37:47 mail kernel: [<ffffffff810536c9>] warn_slowpath_fmt+0x41/0x43
Jan 7 00:37:47 mail kernel: [<ffffffff813e12bf>] ? netif_tx_lock+0x44/0x6c
Jan 7 00:37:47 mail kernel: [<ffffffff813e1427>] dev_watchdog+0xf3/0x164
Jan 7 00:37:47 mail kernel: [<ffffffff8105f320>] ? cascade+0x6a/0x84
Jan 7 00:37:47 mail kernel: [<ffffffff8106316b>] run_timer_softirq+0x1c8/0x270
Jan 7 00:37:47 mail kernel: [<ffffffff8105ae3b>] __do_softirq+0xf8/0x1cd
Jan 7 00:37:47 mail kernel: [<ffffffff8107ef33>] ? tick_program_event+0x2a/0x2c
Jan 7 00:37:47 mail kernel: [<ffffffff81012e1c>] call_softirq+0x1c/0x30
Jan 7 00:37:47 mail kernel: [<ffffffff810143a3>] do_softirq+0x4b/0xa6
Jan 7 00:37:47 mail kernel: [<ffffffff8105aa1b>] irq_exit+0x4a/0x8c
Jan 7 00:37:47 mail kernel: [<ffffffff8146dd32>] smp_apic_timer_interrupt+0x86/0x94
Jan 7 00:37:47 mail kernel: [<ffffffff810127e3>] apic_timer_interrupt+0x13/0x20
Jan 7 00:37:47 mail kernel: <EOI> [<ffffffff812c4c7a>] ? acpi_idle_enter_bm+0x256/0x28a
Jan 7 00:37:47 mail kernel: [<ffffffff812c4c73>] ? acpi_idle_enter_bm+0x24f/0x28a
Jan 7 00:37:47 mail kernel: [<ffffffff813a43b8>] ? cpuidle_idle_call+0x9e/0xfa
Jan 7 00:37:47 mail kernel: [<ffffffff81010c90>] ? cpu_idle+0xb4/0xf6
Jan 7 00:37:47 mail kernel: [<ffffffff81463312>] ? start_secondary+0x201/0x242
Jan 7 00:37:47 mail kernel: ---[ end trace 57f7151f6a5def07 ]---
Jan 7 00:37:47 mail kernel: sky2 eth0: tx timeout
Jan 7 00:37:47 mail kernel: sky2 eth0: transmit ring 79 .. 39 report=79 done=79
Jan 7 00:37:47 mail kernel: sky2 eth0: disabling interface
Jan 7 00:37:47 mail kernel: sky2 eth0: enabling interface
Jan 7 00:37:51 mail kernel: sky2 eth0: Link is up at 1000 Mbps, full duplex, flow control both
JJan 7 00:38:07 mail kernel: sky2 eth0: tx timeout
Jan 7 00:38:07 mail kernel: sky2 eth0: transmit ring 3 .. 90 report=3 done=3
Jan 7 00:38:07 mail kernel: sky2 eth0: disabling interface
Jan 7 00:38:07 mail kernel: sky2 eth0: enabling interface
and so on.
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Next message: KAMEZAWA Hiroyuki: "Re: [PATCH -mmotm] build fix formemcg-move-charges-of-anonymous-swap.patch"
Previous message: Bjorn Helgaas: "Re: BAR 0: can't allocate resource"
In reply to: Michael Breuer: "Re: [PATCH] af_packet: Don't use skb after dev_queue_xmit()"
Next in thread: Michael Breuer: "Re: [PATCH] af_packet: Don't use skb after dev_queue_xmit()"
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