[NTLUG:Discuss] Re: why swap? -- welcome to Gigabit Ethernet

[Bryan J. Smith]

On Fri, 2004-09-10 at 15:16, Robert Citek wrote:
> On the Intel card
> # ifconfig eth0
>            RX packets:831674417 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:905118786 errors:0 dropped:0 overruns:0 carrier:0
> On the Broadcom:
> # ifconfig eth1
>            RX packets:565868899 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:929481655 errors:0 dropped:0 overruns:0 carrier:0

No frame errors.  So the NICs are handling the traffic.
So now it's a TCP/IP issue.

> BTW, turned off swap and transfers improved dramatically.  From another 
> list on which I posted this question:
>    https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=89226
> Seems like an issue with the VM in the kernel:
> # uname -va
> Linux subaru 2.4.20-31.9bigmem #1 SMP Tue Apr 13 17:11:51 EDT 2004 i686 
> athlon i386 GNU/Linux

Hmmm, I wonder how swap works with you already have 4GB of RAM?

Normally once you pass 4GB of RAM, the system performance tanks.
Even though it is virtual, the TLB is still involved, which is 32-bit,
even on PAE36 (64GB) processors (Xeon, Athlon/XP/MP).

Unless you have IA-64 (Itanium) or x86-64 (Athlon64/Opteron).  IA-32e
(aka EM64T) seems to still have some 32-bit architectural limitations
outside the CPU.

But I'm probably barking up the wrong tree.
-- 
     Linux Enthusiasts call me anti-Linux.
   Windows Enthusisats call me anti-Microsoft.
 They both must be correct because I have over a
decade of experience with both in mission critical
environments, resulting in a bigotry dedicated to
 mitigating risk and focusing on technologies ...
           not products or vendors
--------------------------------------------------
Bryan J. Smith, E.I.         b.j.smith at ieee.org