Hi, I did several benchmarks using 3Com 3C940 Gigabit Ethernet adapter (SK98LIN card driver) and it seems there is a weird behavior when using jumbo frames (MTU 9000): The throughput for plain IP is 723 Mbits/sec, but when I enable IPSec (AH only, MD5) I can get up to 745 Mbits/sec!
The fact that makes me believe its a driver issue is that using another NIC (Intel e1000) I get normal results (IP tput > IPSec tput). Also, using 1500 bytes MTU gives normal results. Testbed configuration: Two identical PCs, connected back to back, Intel P4 (1.8GHz), 256MB RAM, 3Com 3C940 and Intel e1000 NICs. Kernel version: 2.6.11.7 /proc/sys/net/core/wmem_max: 16777216 /proc/sys/net/core/rmem_max: 16777216 /proc/sys/net/ipv4/tcp_rmem: 16384 349520 16777216 /proc/sys/net/ipv4/tcp_wmem: 16384 262144 16777216 Benchmark sw: netperf 2.3pl1 Test time: 10 and 60 secs (the results are identical) Socket size: 0 (use system default) Packet send sizes: 64 128 256 512 1024 2048 4096 8192 16384 32768 Kbytes Below you can find the exact throughput, for different packet sizes in both cases (with and without IPSec) /* Plain IP */ Packet size Throughput (bytes) (Mbits/sec) 64 319.14 128 528.16 256 718.42 512 708.09 1024 716.29 2048 721.24 4096 722.43 8192 722.88 16384 721.54 32768 723.00 /* IPSec, AH only, MD5 */ Packet size Throughput (bytes) (Mbits/sec) 64 238.30 128 357.00 256 494.73 512 573.97 1024 635.69 2048 688.75 4096 714.89 8192 735.02 16384 742.04 32768 744.81 As you can see, the problem occurs for packets bigger than 4k. -- Michael Iatrou - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
