Re: [gentoo-user] SATA tuning ?

[Meino Christian Cramer <Meino.Cramer@gmx.de>]

From: "Richard Fish" <bigfish@asmallpond.org>
Subject: Re: [gentoo-user] SATA tuning ?
Date: Tue, 15 Aug 2006 10:32:17 -0700

Hi Richard,
 
 thank you for answering ! :)

> On 8/15/06, Meino Christian Cramer <Meino.Cramer@gmx.de> wrote:
> > Hi,
> >
> >  since SATA does not support DMA I would be interested in other ways
> >  to tune the SATA interface.
> 
> Huh?  SATA _does_ support DMA, and it is always enabled.
> 
> >  Does someone knows some working things to do for tuning the SATA
> >  interface?
> 
> If you have chosen the correct driver in the your kernel
> configuration, it is self-tuning.  There is no more performance to be
> had generally.
> 
> What problem are you trying to solve?  What does "hdparm -Tt /dev/sda"
> actually report?

 I used the following:

    #
    # Please see Documentation/ide.txt for help/info on IDE drives
    #
    # CONFIG_BLK_DEV_IDE_SATA is not set
    ...
    #
    # SCSI low-level drivers
    #
    ...
    CONFIG_SCSI_SATA=y
    ...
    CONFIG_SCSI_SATA_VIA=y
    
    (scsi support is enabled also)

 Just as an info: lspci say:

   00:00.0 Host bridge: VIA Technologies, Inc. K8T800Pro Host Bridge
   00:00.1 Host bridge: VIA Technologies, Inc. K8T800Pro Host Bridge
   00:00.2 Host bridge: VIA Technologies, Inc. K8T800Pro Host Bridge
   00:00.3 Host bridge: VIA Technologies, Inc. K8T800Pro Host Bridge
   00:00.4 Host bridge: VIA Technologies, Inc. K8T800Pro Host Bridge
   00:00.7 Host bridge: VIA Technologies, Inc. K8T800Pro Host Bridge
   00:01.0 PCI bridge: VIA Technologies, Inc. VT8237 PCI bridge [K8T800/K8T890 South]
   00:0a.0 Ethernet controller: Marvell Technology Group Ltd. 88E8001 Gigabit Ethernet Controller (rev 13)
   00:0b.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture (rev 11)
   00:0b.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture (rev 11)
   00:0c.0 Multimedia controller: Sigma Designs, Inc. REALmagic Hollywood Plus DVD Decoder (rev 02)
   00:0d.0 SCSI storage controller: LSI Logic / Symbios Logic 53c875 (rev 03)
   00:0f.0 RAID bus controller: VIA Technologies, Inc. VIA VT6420 SATA RAID Controller (rev 80)
   00:0f.1 IDE interface: VIA Technologies, Inc. VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06)
   00:10.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
   00:10.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
   00:10.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
   00:10.3 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
   00:10.4 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 86)
   00:11.0 ISA bridge: VIA Technologies, Inc. VT8237 ISA bridge [KT600/K8T800/K8T890 South]
   00:11.5 Multimedia audio controller: VIA Technologies, Inc. VT8233/A/8235/8237 AC97 Audio Controller (rev 60)
   00:11.6 Communication controller: VIA Technologies, Inc. AC'97 Modem Controller (rev 80)
   00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
   00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
   00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
   00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
   01:00.0 VGA compatible controller: ATI Technologies Inc Radeon RV200 QW [Radeon 7500]

 hdparm reports on a system, where no other task is running:

    solfire:Mail/vim>sudo hdparm -tT /dev/sda
    /dev/sda:
    Timing cached reads:   2996 MB in  2.00 seconds = 1499.13 MB/sec
    Timing buffered disk reads:  174 MB in  3.01 seconds =  57.79 MB/sec

 which is slightly faster then my previous PATA setup.

 BUT

 WHen doing things, which mixes higher CPU-loads with  massive hd
 utilization, things are going slow (compilation of Blender for
 example).

 It /seems/, that SATA uses more of the CPU capacity than PATA.
 I read the information about "SATA not DMA capable" in the Net. As I
 said: Partly contradictionary....

 And it seems that DMA is only possible with NCQ enabled, which is
 currently (linux 2.6.17.8, vanilla) not the case with the kernel.

 But as said before: This infos are all of "copy and paste" nature...I
 have no way to proof them!!! Thats why I post my question...

> -Richard
> -- 
> gentoo-user@gentoo.org mailing list
> 

Keep hacking!
Meino
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