[coreboot] lower memory performance with coreboot on KGPE-D16

[Iru Cai]

Hi Daniel,

Thanks for your reply, but it's not the case with me.

I'm not using DDR3L-RDIMMs. My dmidecode output of one DIMM is:

Handle 0x0007, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x0006
    Error Information Handle: Not Provided
    Total Width: 72 bits
    Data Width: 64 bits
    Size: 16384 MB
    Form Factor: DIMM
    Set: None
    Locator: NODE 0 DIMM_A2
    Bank Locator: Not Specified
    Type: DDR3
    Type Detail: Synchronous Registered (Buffered)
    Speed: 800 MT/s
    Manufacturer: Samsung
    Serial Number: 7FCC9C13
    Asset Tag: Not Specified
    Part Number: M393B2G70BH0-CK0
    Rank: 2
    Configured Memory Speed: 800 MT/s
    Minimum Voltage: 1.5 V
    Maximum Voltage: 1.5 V
    Configured Voltage: 1.5 V

Iru

On Sat, Oct 6, 2018 at 3:58 AM Daniel Kulesz <daniel.ina1 at googlemail.com>
wrote:

> Hi Iru,
>
> > I just found the memory performance on KGPE-D16 is lower when running
> with
> > coreboot. I have two Opteron 6276 and 8 16GB DDR3-1600 RDIMM on all
> orange
> > slots. I tested it with `hdparm -tT /dev/sda` and see the `Timing cached
> > reads` result. With coreboot, this value is around 3000 MB/s, but with
> OEM
> > firmware it can go to around 3600 MB/s. I think the disk cached read
> speed
> > is related to memory performance.
>
> Are you using DDR3L-RDIMMs? And did you check whether your memory really
> runs at 800 MHz? My experience is that coreboot sets the clock down to 667
> MHz when running on 1.35V (low voltage), while the vendor bios seems to run
> modules at 800 MHz in low voltage mode,  resulting in higher performance.
> According to Timothy, this is  "over the spec" and thus not set in coreboot
> by default (you can choose between 1.5V 800 MHz or 1.35V at 667 MHz - but
> may depend on the used modules).
>
> You can check e.g. in dmidecode. Below is an example (serial number x'd
> out):
>
> Handle 0x000E, DMI type 17, 40 bytes
> Memory Device
>         Array Handle: 0x0006
>         Error Information Handle: Not Provided
>         Total Width: 72 bits
>         Data Width: 64 bits
>         Size: 8192 MB
>         Form Factor: DIMM
>         Set: None
>         Locator: NODE 0 DIMM_D2
>         Bank Locator: Not Specified
>         Type: DDR3
>         Type Detail: Synchronous Registered (Buffered)
>         Speed: 800 MHz
>         Manufacturer: Samsung
>         Serial Number: xxxxxxxxx
>         Asset Tag: Not Specified
>         Part Number: M393B1K70DH0-YK0
>         Rank: 2
>         Configured Clock Speed: 800 MHz
>         Minimum Voltage: 1.35 V
>         Maximum Voltage: 1.5 V
>         Configured Voltage: 1.5 V
>
> Btw.: I am getting around 3700 MB/sec with hdparm -Tt on my /dev/sda
> (mechanical disk) and around 3840 MB/sec on /dev/nvme0n1 (PCIe M.2 SSD).
>
> Cheers, Daniel
>


-- 
My website: https://vimacs.lcpu.club

Please do not send me Microsoft Office/Apple iWork documents. Send
OpenDocument instead! http://fsf.org/campaigns/opendocument/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.coreboot.org/pipermail/coreboot/attachments/20181007/2c923a36/attachment.html>