Re: sendfile() broken with 2.6.26 + Apache 2 ?

From: J. K. Cliburn
Date: Wed Jul 16 2008 - 09:39:19 EST

Eric Dumazet wrote:
Ian Jeffray a écrit :
Hi Eric,

Thanks for directing me to a better list.

Further responses below:

Eric Dumazet wrote:
CC to netdev where this report might find better answers

Ian Jeffray a écrit :

I moved from kernel to 2.6.26 yesterday and observed that
large files sent via Apache2 are partially corrupt.

This appears to be linked to sendfile() -- disabling the use of
sendfile in the apache config (EnableSendfile Off) allows it to
function as normal.

What kind of network adapter are you using ? (lspci | grep -i ether)

02:00.0 Ethernet controller: Attansic Technology Corp. L1 Gigabit Ethernet Adapter (rev b0)

If you disable TCP segmentation offload on this NIC (ethtool -K eth0 tso off) , is this problem still present ?

Wow. That 'solves' the problem! Great.

Does this therefore point to an attansic driver issue?

Yes, maybe related to commit 9d90fb1ac9d97da86e24d9ea947bf2a2f333829a
In this patch, Jay Cliburn enabled TSO by default for atl1 driver.

This might be a driver problem, or a generic sendfile() problem, I dont know...

I'm currently traveling and unable to delve into this issue and its relation to the atl1 driver. I should be able to look at it this weekend when I get back home.

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