On Sep 16, 2009, at 11:34 AM, John Robinson wrote:
Were you using a SiI3124-1 (1.5Gbps, they claim 150MB/s) or SiI3124-2 (3Gbps/300MB/s)?
Actually, it's a 3132 (which is just the PCI-e version of the 3124-2).
What throughput can you get using all 4 channels of the SiI3124 simultaneously, not using the port multiplier - does that top out at 120MB/s too?
It's only got two ports enabled, and they're both eSATA ports. So, I can't really answer that question. However, given that these are known to top out at 120MB/s in a PCI-e slot that doesn't support payload size increase, I would guess it would.
And have you done similar testing of your port multiplier hanging off a motherboard SATA port? Do you get anywhere nearer the 3Gbps?
Yes, I tested an eSATA port on one motherboard and an internal SATA port to eSATA setup on another motherboard. In both cases, the motherboards used the ahci driver for the port under test, and in both cases the ahci ports didn't support FIS command switching. As a result, they both performed even worse, capping out at around 80MB/s. FIS switching is more or less mandatory if you want good performance of a port multiplier link.
-- Doug Ledford <dledford@xxxxxxxxxx> GPG KeyID: CFBFF194 http://people.redhat.com/dledford InfiniBand Specific RPMS http://people.redhat.com/dledford/Infiniband
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