Date: Tue, 14 Nov 2000 17:33:48 -0500 From: David Jones <dej@inode.org> To: Jin Guojun (DSD staff) <jin@george.lbl.gov>, freebsd-hardware@FreeBSD.ORG Subject: Re: Luna 340 Message-ID: <00111417334807.00296@coup.inode.org> In-Reply-To: <200011141626.eAEGQoC27593@portnoy.lbl.gov>
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On November 14, 2000 11:26 am, Jin Guojun (DSD staff) wrote: > The issue is that what will be the performance dropped if the card is > plugged in a 32-bit 33 MHz PCI slot. According to the data sheet, the > MD5 performance is 100 Mbps. On a 32-bit 33 MHz PCI system, it all means > that the performance will be dropped to 50Mbps, right? There are two factors involved here: the CPU power on the chip required to do MD5, and the PCI bus bandwidth required to transfer the information. 32-bit 33 MHz PCI has a theoretical throughput of 132 MBps, or just over 1 Gbps. This is more than enough to handle the MD5 requirement: 100 Mbps just to suck the data in. Note that you will never get near this in the real world; PCI reads are slow. The real issue is the performance on multiple streams of 3DES+MD5, which is where the PCI system will be stressed. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the messagehome | help
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