Re: CVS commit: src/sys

[Jason Thorpe <thorpej%me.com@localhost>]

> On May 25, 2018, at 11:23 AM, Jaromír Doleček <jaromir.dolecek%gmail.com@localhost> wrote:
> 
> 2018-05-22 12:18 GMT+02:00 Martin Husemann <martin%duskware.de@localhost>:
>> Here are timing results:
> 
> While 37% speedup is nice, I see there isn't nearly as huge difference
> as for my machine. Could you please try with some file which fits
> whole in the page cache?
> 
>> Unfortunatley with ubc_direct enabled, it panics quickly:
> 
> There is a comment in uvm_bio.c about some platforms not being able to
> write to individual bytes atomically, and hence software having to do
> read/modify/write. Could this be  somehow causing the machine check on
> Alpha?

I don’t think that’s what’s happening here… from the machine check logout frame that Ross Harvey so kindly decoded in the 21272 Core Logic driver, it looks like a bogus bus_space_read_something to a PCI memory region is happening (it’s a Target Abort on a PCI memory read … it’s been a while, but I think I’m interpreting that right…)

32-bit PCI address:      address  = 0x38d67870, 0x0<No DAC>

It would be instructive to see what PCI device has a memory BAR that covers that address.

If there isn’t one, then I suspect we’re looking at a memory stomper.

> Jaromir

-- thorpej