Messages in this thread | | | Date | Wed, 17 Jun 2009 23:45:50 +0200 | From | "J.A. Magallón" <> | Subject | Re: Speed of SDHCI subsystem |
| |
On Wed, 3 Jun 2009 08:33:41 +0200, Pierre Ossman <drzeus-list@drzeus.cx> wrote:
> On Tue, 19 May 2009 00:37:50 +0200 > "J.A. Magallón" <jamagallon@ono.com> wrote: > > > Hi all... > > > > I have notice something strange with SD cards. > > I have an Aspire One and had an 8Gb SDHC card that used for my home, > > and have recently upgraded to a 16Gb one. > > This new one came with an USB reader. > > > > The thing is that cards look much faster when accessed through the USB > > key that directly on the readers of the One. > > > > Some numbers with hdparm: > > > > TakeMS 8Gb Class 6: > > Gives 10MB/s on the slot, 17MB/s via the USB key > > SanDisk UltraII 16Gb, Class 4, advertised as 15Mb/s: > > Gives 10MB/s on the slot, 14MB/s on USB > > > > I know that hdparm is not a benchmark, but I supposed it should be > > limited by the media, not the connection. > > > > But somehow the SDHCI/MMC subsystem seems to be stuck at 10MB/s, independent > > of the quality of the media. > > > > Any ideas ? > > > > Given your numbers I'd guess that your USB reader supports high-speed > and your built-in one does not. The theoretical throughput without > high-speed is 12.5 MB/s (SI-prefix). With some overhead, and the fact > that many controllers have a lower maximum frequency than 25 MHz, makes > your 10 MB/s pretty reasonable. > > For reference, I've managed to achieve ~23 MB/s using a Sandisk Extreme > III card and a JMicron controller, so there doesn't seem to be any > major inherent bottle necks in the MMC stack. >
Thanks, now its clear it is related to hardware limits. I suppose this controler is a cheap one... Things in the Aspire One are these:
one:~# lspci 00:00.0 Host bridge: Intel Corporation Mobile 945GME Express Memory Controller Hub (rev 03) 00:02.0 VGA compatible controller: Intel Corporation Mobile 945GME Express Integrated Graphics Controller (rev 03) 00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03) 00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 02) 00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 1 (rev 02) 00:1c.1 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 2 (rev 02) 00:1c.2 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 3 (rev 02) 00:1c.3 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 4 (rev 02) 00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #1 (rev 02) 00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #2 (rev 02) 00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #3 (rev 02) 00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #4 (rev 02) 00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 02) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2) 00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 02) 00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7 Family) SATA IDE Controller (rev 02) 00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 02) 02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller (rev 02) 03:00.0 Ethernet controller: Atheros Communications Inc. AR242x 802.11abg Wireless PCI Express Adapter (rev 01) 04:00.0 System peripheral: JMicron Technologies, Inc. SD/MMC Host Controller 04:00.2 SD Host controller: JMicron Technologies, Inc. Standard SD Host Controller 04:00.3 System peripheral: JMicron Technologies, Inc. MS Host Controller 04:00.4 System peripheral: JMicron Technologies, Inc. xD Host Controller
one:~# lspci -vvv -s 04:00.2 04:00.2 SD Host controller: JMicron Technologies, Inc. Standard SD Host Controller (prog-if 01) Subsystem: Acer Incorporated [ALI] Device 015b Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Interrupt: pin A routed to IRQ 19 Region 0: Memory at 34100200 (32-bit, non-prefetchable) [size=256] Capabilities: [a4] Power Management version 3 Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-) Status: D0 PME-Enable- DSel=0 DScale=0 PME- Capabilities: [80] Express (v1) Endpoint, MSI 00 DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s <64ns, L1 <1us ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset- DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported- RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop- MaxPayload 128 bytes, MaxReadReq 128 bytes DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq+ AuxPwr- TransPend- LnkCap: Port #1, Speed 2.5GT/s, Width x1, ASPM L0s L1, Latency L0 unlimited, L1 unlimited ClockPM- Surprise- LLActRep- BwNot- LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- Retrain- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- Capabilities: [94] MSI: Mask- 64bit- Count=1/1 Enable- Address: fffffffc Data: 0000 Kernel modules: sdhci-pci
-- J.A. Magallon <jamagallon()ono!com> \ Software is like sex: \ It's better when it's free Mandriva Linux release 2010.0 (Cooker) for x86_64 Linux 2.6.29.3-desktop-1mnb (gcc 4.3.2 (GCC) #1 Wed May -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |