Re: tuning TCP/IP performance from Carbon app.
Re: tuning TCP/IP performance from Carbon app.
- Subject: Re: tuning TCP/IP performance from Carbon app.
- From: "Peter Sichel" <email@hidden>
- Date: Tue, 13 May 2003 14:58:59 -0400
>
Hello all. I have a question re: how to tune TCP/IP performance from a
>
Carbon application using OpenTransport.
>
>
...
>
On OS 9, using IPNetTuner, it appears I need to change the following
>
settings:
>
>
tcp_rwin_mss_multiplier
>
tcp_dupack_fast_retransmit
>
tcp_mss_max
>
tcp_rexmit_interval_min
>
tcp_rexmit_interval_initial
>
tcp_mss_min
>
tcp_mss_def
>
tcp_rexmit_interval_max
You can get and set these using Mentat's Named Dispatch mechanism.
Quinn's OTDumpArpCache sample shows the basic technique.
If you are running on a Mac OS X system, using "Open Transport"
to tune the classic network stack only affects applications running
under Classic. Conversely, tuning the Mac OS X native BSD stack does
not help applications running under Classic. Depending on your needs,
it might be practical to license IPNetTuner or some of its code.
>
...
>
On OS X I find I need to change completely different options [which makes
>
sense I guess since the IP stacks are of totally different origin].
>
>
net.inet.tcp.delayed_ack
>
net.inet.tcp.recvspace
>
net.inet.tcp.sendspace
>
net.inet.udp.recvspace
>
For Mac OS X, you need to use sysctl from a process with
root privileges, typically a set uid root helper tool.
Quinn's MoreAuthSample can help get you started.
These are the kinds of issues that convinced me two years ago
to rewrite everything in Cocoa using Project Builder (since Code
Warrior didn't support Mach-O yet). Notice Code Warrior still
doesn't support developing Network Kernel Extensions and Apple
is rumored to be working on a new 64-bit CPU family (PPC 970).
- Peter Sichel
Sustainable Softworks
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