Date: Thu, 19 Feb 2004 15:56:15 +0100 From: Marian Durkovic <md@bts.sk> To: freebsd-net@freebsd.org Subject: Solution: TX performance problems with 3Com 905C cards Message-ID: <20040219145615.GB80953@us.svf.stuba.sk> In-Reply-To: <20040217154148.GA85482@us.svf.stuba.sk> References: <20040216170733.GA37519@us.svf.stuba.sk> <20040217154148.GA85482@us.svf.stuba.sk>
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Hi all, the performance problem seems to disappear, when the hardware checksuming for TX direction is disabled (RX hw checksuming still on). Here are the results: otherbox -> box with 3c905C: Bytes Real s CPU s Real-MBit/s CPU-MBit/s Calls Real-C/s CPU-C/s l409600000 34.80 2.89 94.1488 1134.2671 100000 2873.19 34615.1 1409600000 34.82 1.21 94.1173 2707.3675 281392 8082.24 232492.5 box with 3c905C -> otherbox: Bytes Real s CPU s Real-MBit/s CPU-MBit/s Calls Real-C/s CPU-C/s l409600000 34.91 1.20 93.8721 2737.7209 282783 8101.03 236261.3 1409600000 34.90 1.67 93.8939 1962.4189 100000 2865.41 59888.3 With kind regards, M. > I'm experiencing some performance issues with 3Com 905C cards @ FreeBSD 4.8 > When running nttcp tests with other servers, the result is: > > otherbox -> box with 3c905 > > Bytes Real s CPU s Real-MBit/s CPU-MBit/s Calls Real-C/s CPU-C/s > l409600000 34.80 2.96 94.1489 1105.1982 100000 2873.20 33728.0 > 1409600000 34.82 1.18 94.1175 2773.2828 281323 8080.27 238094.6 > > box with 3c905 -> otherbox > > Bytes Real s CPU s Real-MBit/s CPU-MBit/s Calls Real-C/s CPU-C/s > l409600000 38.86 1.18 84.3323 2766.3223 282788 7277.88 238733.7 > 1409600000 38.85 1.56 84.3524 2100.2557 100000 2574.23 64094.7 > > The above data shows that 3c905C is able to receive data at full wire speed > of FastEthernet since the value corresponds to its theoretical maximum. > However, when 3c905C is transmitting data, the rate drops to 84 Mbps.
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