Re: [PATCH] speed up SATA

From: Jeff Garzik
Date: Tue Mar 30 2004 - 12:46:06 EST

Marc Bevand wrote:
I think I am reaching the physical limit of the PCI bus (theoretically it
would be 133 MB/s or 133000 blocks/s). When setting the PCI latency timer of
the SiI3114 controller to 240 (was 64), I am able to reach 100000 blocks/s.

That's interesting.

I wonder if we should look at making pci_set_master()'s latency timer setting code be a bit smarter.

It (pcibios_set_master in arch/i386/pci/i386.c) current checks the latency timer value programmed by the BIOS. If the BIOS did not initialize the value, then it is set to 64. Otherwise, it is clamped to the maximum 255.

I wonder if your BIOS shouldn't increase that latency timer value...?


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