[Linux-ATM-General] rx drop

[Massey, J. <James.Massey@Goodrich.com>]

Hi,

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I am running an application which acquires data from 3 Interphase 5575
card and dumps the data to disk.=20

A separate process reads the data from disk, performs some data
transformations and outputs files to another machine over Gigabit
Ethernet via NFS.

The data is acquired using the Linux ATM API (sockets) using the AAL5
protocol.

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When the system is run over a period of time (~5 mins) packets are being
dropped as indicated by the RX_drop count increasing in atmdiag.

Referring to /net/atm/atm_misc.c in the kernel source tree, it appears
that the reason for the drop is lack of network stack buffers when
calling atm_alloc_charge.

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Is there any way to increase the buffer space available to the ATM
network stack?

Does setting net.core.rmem.default and net.core.rmem_max achieve this?

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The operating system version is Suse Linux Enterprise Server 9 and the
kernel version is 2.6.5-7.191-bigsmp.

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Cheers

James Massey

Goodrich SRS Limited

Malvern Hills Science Park

Malvern

Worcs

WR14 3SZ

01684-585335

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