Re: AMD Phenom - need to enable L3 cache?

[Chris Gilbert <chris%dokein.co.uk@localhost>]

Christoph Egger wrote:
> Chris Gilbert wrote:
> > Christoph Egger wrote:
> > > Paul Goyette wrote:
> > > > I've just worked up a change to cpuctl to display L3 cache information
> > > > (see PR bin/38679), and it appears that we don't have the L3 cache 
> > > > enabled:
> > > >
> > > > speedy {101} /build/obj/amd64/usr.sbin/cpuctl/cpuctl identify 0
> > > > Cannot bind to target CPU.  Output may not accurately describe the 
> > > > target.
> > > > Run as root to allow binding.
> > > >
> > > > cpu0: AMD Family 10h (686-class), 2310.80 MHz, id 0x100f22
> > > > cpu0: features 
> > > > ffdbfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR>
> > > > cpu0: features ffdbfbff<PGE,MCA,CMOV,PAT,PSE36,MPC,NOX,MMXX,MMX>
> > > > cpu0: features ffdbfbff<FXSR,SSE,SSE2,RDTSCP,HTT,LONG,3DNOW2,3DNOW>
> > > > cpu0: features2 802009<SSE3,MONITOR,CX16,POPCNT>
> > > > cpu0: "AMD Phenom(tm) 9600 Quad-Core Processor"
> > > > cpu0: I-cache 64kB 64B/line 2-way, D-cache 64kB 64B/line 2-way
> > > > cpu0: L2 cache 512kB 64B/line 16-way
> > > > cpu0: ITLB 32 4KB entries fully associative, 16 4MB entries fully 
> > > > associative
> > > > cpu0: DTLB 48 4KB entries fully associative, 48 4MB entries fully 
> > > > associative
> > > > cpu0: L3 cache 2048kB 64B/line disabled
> > > > cpu0: Initial APIC ID 1
> > > > cpu0: family 0f model 02 extfamily 01 extmodel 00
> > > >
> > > > Is there some explicit initialization needed to enable the L3 cache?
> > >
> > > It is disabled by the BIOS on stepping 2 (TLB-Bug).
> > > Stepping 3 has L3 cache enabled.
> >
> > That's not how it's worked around, it disable caching of the PTPs.
> >
> > Actually the table amd_cpuid_l2cache_assoc_info needs an update, it 
> > needs extending to support extra values for L3 caches.
>
> I already did that. See sys/arch/x86/x86/identcpu.c

Sadly it's not shared with cpuctl.  Also the amd_cpuid_l3cache_assoc 
table is wrong, it shouldn't have a row of zeros at the start.  It 
causes premature termination, see cache_info_lookup.

I'd been meaning to test it, but lack time and my phenom needs a 
reinstall I managed to get a busted ssh implementation on it so can't 
sync the source tree.

Thanks
Chris