Re: AFP tuning
Re: AFP tuning
- Subject: Re: AFP tuning
- From: Dario <email@hidden>
- Date: Mon, 12 Apr 2004 01:05:34 +0200
Hi All,
I'm fiddling around with AppleFileServer trying to improve performance.
Using ktrace, a modified netstat that shows window size and tcpdump, I
can see that afp is doing ~12k writes (8 packets of 1448 each per
sequential tcp burst), using only one tcp socket for all transfers,
and setting a fairly anemic window size of 64k (although in the actual
transfer, I see it's 32k)
There is not only the tcp frame size to care of, it seems that the data
is sent throught a ethernet interface, since it's mtu is 1500byte. try
increasing it to the jumbo size (9600) and the tcp packet will be
longer
Here's a short burst:
08:14:57.552720 IP (tos 0x0, ttl 64, id 10531, offset 0, flags [DF],
length: 1500) 192.168.1.100.afpovertcp > 192.168.1.103.49236: .
1168:2616(1448) ack 579 win 32768 <nop,nop,timestamp 3673937391
3937036659>
08:14:57.553335 IP (tos 0x0, ttl 64, id 10532, offset 0, flags [DF],
length: 1500) 192.168.1.100.afpovertcp > 192.168.1.103.49236: .
2616:4064(1448) ack 579 win 32768 <nop,nop,timestamp 3673937391
3937036659>
08:14:57.553640 IP (tos 0x0, ttl 64, id 10533, offset 0, flags [DF],
length: 1500) 192.168.1.100.afpovertcp > 192.168.1.103.49236: .
4064:5512(1448) ack 579 win 32768 <nop,nop,timestamp 3673937391
3937036659>
08:14:57.553951 IP (tos 0x0, ttl 64, id 10534, offset 0, flags [DF],
length: 1500) 192.168.1.100.afpovertcp > 192.168.1.103.49236: .
5512:6960(1448) ack 579 win 32768 <nop,nop,timestamp 3673937391
3937036659>
08:14:57.554266 IP (tos 0x0, ttl 64, id 10535, offset 0, flags [DF],
length: 1500) 192.168.1.100.afpovertcp > 192.168.1.103.49236: .
6960:8408(1448) ack 579 win 32768 <nop,nop,timestamp 3673937391
3937036659>
08:14:57.554573 IP (tos 0x0, ttl 64, id 10536, offset 0, flags [DF],
length: 1500) 192.168.1.100.afpovertcp > 192.168.1.103.49236: .
8408:9856(1448) ack 579 win 32768 <nop,nop,timestamp 3673937391
3937036659>
08:14:57.554884 IP (tos 0x0, ttl 64, id 10537, offset 0, flags [DF],
length: 1500) 192.168.1.100.afpovertcp > 192.168.1.103.49236: .
9856:11304(1448) ack 579 win 32768 <nop,nop,timestamp 3673937391
3937036659>
08:14:57.555210 IP (tos 0x0, ttl 64, id 10538, offset 0, flags [DF],
length: 1500) 192.168.1.100.afpovertcp > 192.168.1.103.49236: .
11304:12752(1448) ack 579 win 32768 <nop,nop,timestamp 3673937391
3937036659>
Here's the window size:
spongebob:/Users/modica root# ./ns
Active Internet connections
Proto Recv-Q/Window Send-Q/Window Local Address Foreign
Address (state)
tcp4 0/ 65536 0/ 65536 192.168.1.103.afpovert
192.168.1.100.49331 ESTABLISHED
tcp4 0/ 66608 0/ 66608 192.168.1.103.49236
192.168.1.100.afpovert ESTABLISHED
I found some documentation refering to parameters being set in NetInfo
manager under /config/AppleFileServer but when I attempted to set
TCPQuantum in there, it was just ignored (even after a reboot). Are
these values simply hardcoded into the daemon? Can one set things
like afpTCPPort and TCPQuantum or are they just ignored?
Best Regards!
Steve
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