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Message-Id: <200908222129.02984.volkerarmin@googlemail.com> Date: Sat, 22 Aug 2009 21:29:02 +0200 From: Volker Armin Hemmann <volkerarmin@...glemail.com> To: linux-kernel@...r.kernel.org Subject: Re: amd64 + mtrr: only 3.1gb of 8gb are covered, kernel 2.6.30 and earlier. On Samstag 22 August 2009, you wrote: > On Sat, Aug 22, 2009 at 11:54 AM, Volker Armin > > Hemmann<volkerarmin@...glemail.com> wrote: > > On Samstag 22 August 2009, Yinghai Lu wrote: > >> On Fri, Aug 21, 2009 at 9:14 AM, Volker Armin > >> > >> Hemmann<volkerarmin@...glemail.com> wrote: > >> > Hi, > >> > > >> > I have an amd64 system with 8GB ram. Of these only 3.1GB are currently > >> > covered with mtrr: > >> > cat /proc/mtrr > >> > reg00: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back > >> > reg01: base=0x080000000 ( 2048MB), size= 1024MB, count=1: write-back > >> > reg02: base=0x0c0000000 ( 3072MB), size= 128MB, count=1: write-back > >> > > >> > This is with a Phenom II X4. Mobo is an Asrock A770Crossfire with AMD > >> > 770 chipset. Ram is 1066 ddr2 running at 800. > >> > > >> > Before that I had a X2 6000 where I had one more mtrr, covering > >> > additional 256mb with 6gb ram total. > >> > > >> > When I use the opensource driver, I get a 'mtrr disabled' message when > >> > X starts, nothing like that with fglrx. The results are the same. > >> > > >> > Is there anything that I can do about it? I already played with mtrr > >> > cleanup options - without any results. > >> > > >> > Except for reiser4 the kernel is 'vanilla', config is attached, dmesg > >> > and lspci are folloiwing: > >> > > >> > dmesg: > >> > [ 0.000000] Linux version 2.6.30.5r4 (root@...rgy) (gcc version > >> > 4.4.1 (Gentoo 4.4.1 p1.0) ) #1 SMP Tue Aug 18 06:28:18 CEST 2009 > >> > [ 0.000000] Command line: root=/dev/md1 > >> > md=3,/dev/sda3,/dev/sdb3,/dev/sdc3 nmi_watchdog=0 mtrr_spare_reg_nr=1 > >> > [ 0.000000] KERNEL supported cpus: > >> > [ 0.000000] Intel GenuineIntel > >> > [ 0.000000] AMD AuthenticAMD > >> > [ 0.000000] BIOS-provided physical RAM map: > >> > [ 0.000000] BIOS-e820: 0000000000000000 - 000000000009fc00 > >> > (usable) [ 0.000000] BIOS-e820: 000000000009fc00 - > >> > 00000000000a0000 (reserved) [ 0.000000] BIOS-e820: > >> > 00000000000e6000 - 0000000000100000 (reserved) [ 0.000000] > >> > BIOS-e820: 0000000000100000 - 00000000c7eb0000 (usable) [ > >> > 0.000000] BIOS-e820: 00000000c7eb0000 - 00000000c7ec0000 (ACPI data) > >> > [ 0.000000] BIOS-e820: 00000000c7ec0000 - 00000000c7ef0000 (ACPI > >> > NVS) [ 0.000000] BIOS-e820: 00000000c7ef0000 - 00000000c7f00000 > >> > (reserved) [ 0.000000] BIOS-e820: 00000000fff00000 - > >> > 0000000100000000 (reserved) [ 0.000000] BIOS-e820: > >> > 0000000100000000 - 0000000238000000 (usable) [ 0.000000] DMI > >> > present. > >> > [ 0.000000] AMI BIOS detected: BIOS may corrupt low RAM, working > >> > around it. [ 0.000000] e820 update range: 0000000000000000 - > >> > 0000000000010000 (usable) ==> (reserved) > >> > [ 0.000000] last_pfn = 0x238000 max_arch_pfn = 0x100000000 > >> > [ 0.000000] MTRR default type: uncachable > >> > [ 0.000000] MTRR fixed ranges enabled: > >> > [ 0.000000] 00000-9FFFF write-back > >> > [ 0.000000] A0000-EFFFF uncachable > >> > [ 0.000000] F0000-FFFFF write-protect > >> > [ 0.000000] MTRR variable ranges enabled: > >> > [ 0.000000] 0 base 000000000000 mask FFFF80000000 write-back > >> > [ 0.000000] 1 base 000080000000 mask FFFFC0000000 write-back > >> > [ 0.000000] 2 base 0000C0000000 mask FFFFF8000000 write-back > >> > [ 0.000000] 3 disabled > >> > [ 0.000000] 4 disabled > >> > [ 0.000000] 5 disabled > >> > [ 0.000000] 6 disabled > >> > [ 0.000000] 7 disabled > >> > [ 0.000000] TOM2: 0000000238000000 aka 9088M > >> > [ 0.000000] x86 PAT enabled: cpu 0, old 0x7040600070406, new > >> > 0x7010600070106 > >> > [ 0.000000] e820 update range: 00000000c8000000 - 0000000100000000 > >> > (usable) ==> (reserved) > >> > >> ... > >> > >> > 02:00.0 VGA compatible controller: ATI Technologies Inc Radeon HD 3870 > >> > (prog- if 00 [VGA controller]) > >> > Subsystem: Info-Tek Corp. Device 4070 > >> > Flags: bus master, fast devsel, latency 0, IRQ 30 > >> > Memory at d0000000 (64-bit, prefetchable) [size=256M] > >> > Memory at fdff0000 (64-bit, non-prefetchable) [size=64K] > >> > I/O ports at b000 [size=256] > >> > Expansion ROM at fdfc0000 [disabled] [size=128K] > >> > Capabilities: [50] Power Management version 3 > >> > Capabilities: [58] Express Legacy Endpoint, MSI 00 > >> > Capabilities: [a0] MSI: Mask- 64bit+ Count=1/1 Enable+ > >> > Capabilities: [100] Vendor Specific Information <?> > >> > Kernel driver in use: fglrx_pci > >> > Kernel modules: fglrx > >> > >> after your start X server, how about cat /proc/mtrr? > >> > >> thought there should be one WC entry about 256M... for graphics card. > >> > >> YH > > > > running X: > > > > cat /proc/mtrr > > reg00: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back > > reg01: base=0x080000000 ( 2048MB), size= 1024MB, count=1: write-back > > reg02: base=0x0c0000000 ( 3072MB), size= 128MB, count=1: write-back > > > > back with my X2 6000 and 4 and 6gb ram, I indeed got another mtrr with > > 256mb. But with the phenom and 8gb I don't get it. Neither with fglrx nor > > with xorg's radeon driver. Radeon posts a message to dmesg about disabled > > mtrr. > > you should have > reg03: base=0x0d0000000 ( 3200MB), size= 256MB, count=1: write-combining back with my X2 6000 I had that. > > do you notice any performance degrade without that entry? > > YH when I went from 4gb to 6gb I had a performance degradation. Since the 8gb are faster and the new cpu is faster, I don't see degradation. But I wonder how much better performance could be with 'correct' mtrr. Glück Auf Volker -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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