Comment 23 for bug 194029

Does anyone have any suspicions that the newly released 2.6.25 is
going to help us here? It sounds like there are a lot of tweakins'
coming through the interpipes with this release... Much along the
lines of the NAS additions, (framework)?

On Thu, Mar 27, 2008 at 9:15 PM, Sebastien Estienne
<email address hidden> wrote:
> I'm using 2.6.24-7 and have no issue running synergyc as normal user,
> every version >= 2.6.24-8 have this lagging behaviour.
>
>
>
> --
> 2.6.24-8 Introduces Network Issue
> https://bugs.launchpad.net/bugs/194029
> You received this bug notification because you are a direct subscriber
> of a duplicate bug.
>
> Status in Source Package "linux" in Ubuntu: Incomplete
> Status in Source Package "synergy" in Ubuntu: Confirmed
>
> Bug description:
> I'll apologize right off the bat for lacking more concrete information about this bug, but perhaps you can guide me in isolating the issue better than I could on my own.
>
> After upgrading my kernel (in hardy) to linux-image-2.6.24-8-generic from linux-image-2.6.24-7-generic, I noticed that when using synergyc, input 'hangs' on a regular basis. That is to say that when I move my mouse from the synergy server to the hardy client system, the mouse will only move intermittently, and keyboard input is similarly fragmented. None of the movements or keystrokes are ever actually lost (Synergy uses TCP, so that's expected), but movement is sporadic and jumpy, and keystrokes seem to occasionally get 'buffered' and then arrive all at the same time. I "confirmed" this was a kernel issue by rebooting and selecting the 2.6.24-7 kernel, and the issue disappeared again.
>
> Also potentially of interest is that when I tried to diagnose the behavior by running a packet capture through Wireshark on the problematic client, the issue would never appear while capturing from the nic. Immediately after ending the capture, the issue would again manifest itself.
>
> Even while the synergyc input was 'hung,' there was no apparent packet loss, as measured by a ping flood to the hardy machine.
>
> Release: 8.04/hardy
> Kernel: linux-image-2.6.24-8-generic 2.6.24-8.14
> Architecture: amd64 / x86_64
>
> Hardware (as queried from 2.6.24-7):
> Lenovo Thinkpad T61
> 00:19.0 Ethernet controller: Intel Corporation 82566MM Gigabit Network Connection (rev 03)
> Subsystem: Lenovo ThinkPad T61
> Flags: bus master, fast devsel, latency 0, IRQ 503
> Memory at fe200000 (32-bit, non-prefetchable) [size=128K]
> Memory at fe225000 (32-bit, non-prefetchable) [size=4K]
> I/O ports at 1840 [size=32]
> Capabilities: [c8] Power Management version 2
> Capabilities: [d0] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable+
>
> $ ethtool -i eth0
> driver: e1000
> version: 7.3.20-k2-NAPI
> firmware-version: 0.3-0
> bus-info: 0000:00:19.0
>
> $ ethtool -d eth0
> MAC Registers
> -------------
> 0x00000: CTRL (Device control register) 0x00140240
> Endian mode (buffers): little
> Link reset: normal
> Set link up: 1
> Invert Loss-Of-Signal: no
> Receive flow control: disabled
> Transmit flow control: disabled
> VLAN mode: disabled
> Auto speed detect: disabled
> Speed select: 1000Mb/s
> Force speed: no
> Force duplex: no
> 0x00008: STATUS (Device status register) 0x00080462
> Duplex: half
> Link up: link config
> TBI mode: enabled
> Link speed: 100Mb/s
> Bus type: PCI Express
> Port number: 0
> 0x00100: RCTL (Receive control register) 0x00008002
> Receiver: enabled
> Store bad packets: disabled
> Unicast promiscuous: disabled
> Multicast promiscuous: disabled
> Long packet: disabled
> Descriptor minimum threshold size: 1/2
> Broadcast accept mode: accept
> VLAN filter: disabled
> Canonical form indicator: disabled
> Discard pause frames: filtered
> Pass MAC control frames: don't pass
> Receive buffer size: 2048
> 0x02808: RDLEN (Receive desc length) 0x00001000
> 0x02810: RDH (Receive desc head) 0x00000087
> 0x02818: RDT (Receive desc tail) 0x00000085
> 0x02820: RDTR (Receive delay timer) 0x00000000
> 0x00400: TCTL (Transmit ctrl register) 0x3103F0FA
> Transmitter: enabled
> Pad short packets: enabled
> Software XOFF Transmission: disabled
> Re-transmit on late collision: enabled
> 0x03808: TDLEN (Transmit desc length) 0x00001000
> 0x03810: TDH (Transmit desc head) 0x000000DF
> 0x03818: TDT (Transmit desc tail) 0x000000DF
> 0x03820: TIDV (Transmit delay timer) 0x00000008
> PHY type: unknown
>
>
> When queried from 2.6.24-8, only the following values change (which appear to change between calls to that command anyway):
> 0x02810: RDH (Receive desc head) 0x00000029
> 0x02818: RDT (Receive desc tail) 0x00000027
>
> 0x03810: TDH (Transmit desc head) 0x00000003
> 0x03818: TDT (Transmit desc tail) 0x00000003
>