On Tue, May 24, 2005 at 01:09:38PM -0400, John Heffner wrote:
> On Tuesday 24 May 2005 12:59 pm, Paul Griffith wrote:
> > Greetings,
> >
> > I have been searching the Internet for a final answer what the values
> > in net.ipv4.tcp_mem mean.
> >
> > I have seen some sites say it is in memory pages (4K blocks) and other
> > have said it is in KB. What the real answer?
>
> It's in pages, as described in Documentation/networking/ip-sysctl.txt. A lot
> of people have this wrong. If you find any incorrect sites, could you point
> them out or send mail to their maintainers? I've gotten a few corrected that
> I've noticed so far.
>
> -John
Thanks for cleaning that up. I wanted to know, because I am tasked
with tunning a Linux NFS/SMB server on GigE. Details below:
Hardware:
P4/2.8Ghz/1GB/40GB HDD/G4 FX5200
Intel 865PERL
1) When I boot with v2.4.29 on my local computer tcp_mem set to the
following:
cat /proc/sys/net/ipv4/tcp_mem
49152 65536 98304
(192MB) (256MB) (384MB)
2) When I boot the same computer with Knoppix v3.8.2 - v2.6.11.8 #3
cat /proc/sys/net/ipv4/tcp_mem
196608 262144 393216
(768MB) (1024MB) (1536MB)
3) When I boot the same computer with Slax v5.0.5 - v2.6.11.8 #1
cat /proc/sys/net/ipv4/tcp_mem
98304 131073 196608
(384MB) (512MB) (768MB)
I can understand the change in the tcp stack from 2.4.x to 2.6.x. What
I don't understand is why one level of the 2.6.11.8 #3 kernel will set
my max TCP_MEM to 1.5 * MEMORY and the other 2.6.11.8 #1 sets TCP_MEM
to .75 * MEMORY.
Anyone one has any idea what is going on here???
I am trying to understand the tcp stack in Linux because I have to
tune a GigE Linux based NFS/SMB server to as our departmental
fileserver. The server is currently using the default tcp settings on 2.4.26
[patched to support quotas on RiserFS].
Thanks
Paul
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