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Message-Id: <20080616203832.M12498@visp.net.lb>
Date: Mon, 16 Jun 2008 23:42:42 +0300
From: "Denys Fedoryshchenko" <denys@...p.net.lb>
To: "Waskiewicz Jr, Peter P" <peter.p.waskiewicz.jr@...el.com>,
<netdev@...r.kernel.org>
Subject: RE: packetloss, on e1000e worse than r8169?
On Mon, 16 Jun 2008 13:37:06 -0700, Waskiewicz Jr, Peter P wrote
> >MegaRouter-KARAM /sys # ethtool -S eth1
> >NIC statistics:
> > rx_packets: 109977509
> > tx_packets: 109887692
> > rx_bytes: 57656749138
> > tx_bytes: 57536071746
> > rx_broadcast: 6497
> > tx_broadcast: 92
> > rx_multicast: 48995
> > tx_multicast: 1960
> > rx_errors: 0
> > tx_errors: 0
> > tx_dropped: 0
> > multicast: 48995
> > collisions: 0
> > rx_length_errors: 0
> > rx_over_errors: 0
> > rx_crc_errors: 0
> > rx_frame_errors: 0
> > rx_no_buffer_count: 1796
> > rx_missed_errors: 2182679
>
> This is an indication here that your host isn't processing your Rx fast
> enough, and your Rx ring is out of descriptors. Hence, your
> hardware is needing to drop the packet. What's disturbing is that
> you actually do have flow control packets being processed, so the
> NIC is trying to help the host.
>
> > tx_aborted_errors: 0
> > tx_carrier_errors: 0
> > tx_fifo_errors: 0
> > tx_heartbeat_errors: 0
> > tx_window_errors: 0
> > tx_abort_late_coll: 0
> > tx_deferred_ok: 55617
> > tx_single_coll_ok: 0
> > tx_multi_coll_ok: 0
> > tx_timeout_count: 0
> > tx_restart_queue: 1626
> > rx_long_length_errors: 0
> > rx_short_length_errors: 0
> > rx_align_errors: 0
> > tx_tcp_seg_good: 0
> > tx_tcp_seg_failed: 0
> > rx_flow_control_xon: 55461
> > rx_flow_control_xoff: 57329
> > tx_flow_control_xon: 39114
> > tx_flow_control_xoff: 48341
> > rx_long_byte_count: 57656749138
> > rx_csum_offload_good: 104097306
> > rx_csum_offload_errors: 2209
>
> This is also a bit disturbing, that Rx CSUM offload is running into
> issues. I think though this is due to the rx_no_buffer_count.
>
> I see in a followup email you tried increasing your ring size to 4096
> descriptors. I'd suggest trying 512 descriptors; something slow,
> instead of going for 4096 out of the gate. However, if your host can't
> keep up with 256 descriptors, I think you're just going to prolong your
> problem by increasing your descriptor ring size. But I don't know what
> the profile of your traffic is, so perhaps bumping up the descriptor
> ring size to 512 or even 1024 descriptors might help.
>
If i am not wrong when situation is related to ring, i will have large amount
of errors in rx_no_buffer_count. I tried now 512 and 1024, it doesn't change
anything at all.
MegaRouter-KARAM ~ # ethtool -g eth1
Ring parameters for eth1:
Pre-set maximums:
RX: 4096
RX Mini: 0
RX Jumbo: 0
TX: 4096
Current hardware settings:
RX: 1024
RX Mini: 0
RX Jumbo: 0
TX: 256
MegaRouter-KARAM ~ # ifconfig eth1; sleep 10;ifconfig eth1
eth1 Link encap:Ethernet HWaddr 00:19:D1:71:5F:33
inet addr:192.168.20.10 Bcast:0.0.0.0 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:105760686 errors:0 dropped:1728264 overruns:0 frame:0
TX packets:105667743 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:4291052222 (3.9 GiB) TX bytes:4081974720 (3.8 GiB)
Memory:90300000-90320000
eth1 Link encap:Ethernet HWaddr 00:19:D1:71:5F:33
inet addr:192.168.20.10 Bcast:0.0.0.0 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:106541093 errors:0 dropped:1744393 overruns:0 frame:0
TX packets:106447803 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:413277601 (394.1 MiB) TX bytes:202824806 (193.4 MiB)
Memory:90300000-90320000
rx_no_buffer_count is not a big deal, i had this issue on Sun Fire (e1000 over
PCI-X 66 Mhz), and increasing ring solved the problem. But this case seems
different. My headache now is rx_missed_errors. It can be bus bandwidth hog
also, as i read in maillists, but it's supposed to be x1 PCI-Express with 2.5
GB/s throughput!
--
Denys Fedoryshchenko
Technical Manager
Virtual ISP S.A.L.
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