RE: [Lse-tech] Re: Preliminary results of using multiblock raw I/O

Martin Frey
2001-10-23T09:59:25Z

>I haven't seen the SGI rawio patch, but I'm assuming it used kiobufs to
>pass a single unit of 1 meg down at the time. Yes currently we do incur
>significant overhead compared to that approach.
>
Yes, it used kiobufs to get a gatherlist, setup a gather DMA out
of that list and submitted it to the SCSI layer. Depending on
the controller 1 MB could be transfered with 0 memcopies, 1 DMA,
1 interrupt. 200 MB/s with 10% CPU load was really impressive.

Regards, Martin