Messages in this thread | | | From | David Mosberger <> | Date | Mon, 14 Jul 2003 22:31:00 -0700 | Subject | Re: [patch] e1000 TSO parameter |
| |
[Scott, somehow I never received your original response so I'm replying based on what I saw in the linux.kernel newgroup...]
Scott> Do you have any data to share?
Sure, I don't see why not. Here are the number I got:
TSO disabled:
$ modprobe InterruptThrottleRate=0,0,0,0 TSO=0,0,0,0 $ netperf -l 30 -c -C -H foobar -- -s64K -S64K TCP STREAM TEST to foobar Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB
131070 131072 131072 30.00 897.16 34.07 35.00 3.111 3.196
TSO enabled:
$ modprobe InterruptThrottleRate=0,0,0,0 TSO=1,1,1,1 $ netperf -l 30 -c -C -H foobar -- -s64K -S64K TCP STREAM TEST to foobar Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB
131070 131072 131072 30.00 894.09 11.65 34.48 1.068 3.159
This looks roughly like you'd expect: with TSO, slightly lower throughput but much less CPU overhead.
With ftp, things get stranger: fetching a 2GByte file via ftp get (from the remote end):
TSO disabled:
ftp> get big.iso /dev/null local: /dev/null remote: big.iso 200 PORT command successful. 150 Opening BINARY mode data connection for 'big.iso' (2038628352 bytes). 226 Transfer complete. 2038628352 bytes received in 18.17 secs (109554.5 kB/s)
ftp server CPU utilization: ~ 40%
With TSO enabled:
ftp> get big.iso /dev/null local: /dev/null remote: big.iso 200 PORT command successful. 150 Opening BINARY mode data connection for 'big.iso' (2038628352 bytes). 226 Transfer complete. 2038628352 bytes received in 21.16 secs (94070.2 kB/s)
ftp server CPU utilization: ~ 15%
So we get almost 15% of throughput drop. This was with plain "netkit fptd". AFAIK, it does a simple read/write loop (not sendfile()).
--david - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |