Re: high latency on 82573L

[Tony Jones]

On Thu, Sep 02, 2010 at 11:49:12AM -0700, Allan, Bruce W wrote:
> Please provide more verbose lspci output and include the PCI config
> space, i.e. 'lspci -s 2:0.0 -vvv -xxx' after the driver is loaded,

# lspci -s 2:0.0 -vvv -xxx
02:00.0 Ethernet controller: Intel Corporation 82573L Gigabit Ethernet Controller
	Subsystem: Lenovo ThinkPad T60
	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-
	Latency: 0, Cache Line Size: 64 bytes
	Interrupt: pin A routed to IRQ 46
	Region 0: Memory at ee000000 (32-bit, non-prefetchable) [size=128K]
	Region 2: I/O ports at 3000 [size=32]
	Capabilities: [c8] Power Management version 2
		Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
		Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=1 PME-
	Capabilities: [d0] MSI: Enable+ Count=1/1 Maskable- 64bit+
		Address: 00000000fee0100c  Data: 41c9
	Capabilities: [e0] Express (v1) Endpoint, MSI 00
		DevCap:	MaxPayload 256 bytes, PhantFunc 0, Latency L0s <512ns, L1 <64us
			ExtTag- AttnBtn- AttnInd- PwrInd- RBE- FLReset-
		DevCtl:	Report errors: Correctable+ Non-Fatal+ Fatal+ Unsupported+
			RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
			MaxPayload 128 bytes, MaxReadReq 512 bytes
		DevSta:	CorrErr- UncorrErr+ FatalErr- UnsuppReq+ AuxPwr+ TransPend-
		LnkCap:	Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Latency L0 <128ns, L1 <64us
			ClockPM+ Surprise- LLActRep- BwNot-
		LnkCtl:	ASPM L1 Enabled; 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: [100 v1] Advanced Error Reporting
		UESta:	DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq+ ACSViol-
		UEMsk:	DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
		UESvrt:	DLP+ SDES- TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
		CESta:	RxErr+ BadTLP+ BadDLLP- Rollover- Timeout- NonFatalErr-
		CEMsk:	RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr-
		AERCap:	First Error Pointer: 14, GenCap- CGenEn- ChkCap- ChkEn-
	Capabilities: [140 v1] Device Serial Number 00-1a-6b-ff-ff-6c-7e-a4
	Kernel driver in use: e1000e
00: 86 80 9a 10 07 05 10 00 00 00 00 02 10 00 00 00
10: 00 00 00 ee 00 00 00 00 01 30 00 00 00 00 00 00
20: 00 00 00 00 00 00 00 00 00 00 00 00 aa 17 01 20
30: 00 00 00 00 c8 00 00 00 00 00 00 00 0b 01 00 00
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
c0: 00 00 00 00 00 00 00 00 01 d0 22 c8 00 20 00 0f
d0: 05 e0 81 00 0c 10 e0 fe 00 00 00 00 c9 41 00 00
e0: 10 00 01 00 c1 0c 00 00 1f 28 1a 00 11 1c 07 00
f0: 42 01 11 10 00 00 00 00 00 00 00 00 00 00 00 00

> kernel.  Are there any messages in the system log regarding disabling
> ASPM L0s and/or L1 on that device?

It would appear it is being disabled:

[    0.194271] ACPI FADT declares the system doesn't support PCIe ASPM, so disable it
[    0.297112] pci 0000:01:00.0: disabling ASPM on pre-1.1 PCIe device.  You can enable it with 'pcie_aspm=force'
[    0.298003] pci 0000:02:00.0: disabling ASPM on pre-1.1 PCIe device.  You can enable it with 'pcie_aspm=force'
[    0.299123] pci 0000:03:00.0: disabling ASPM on pre-1.1 PCIe device.  You can enable it with 'pcie_aspm=force'
[   18.135907] e1000e 0000:02:00.0: Disabling ASPM  L1
[   18.137262] e1000e 0000:02:00.0: Disabling ASPM L0s 

but I see the same high ping latencies.

> I can understand the latency with the OpenSUSE 2.6.34-based kernels
> assuming commit 19833b5dff is not present, but I do not understand
> the latency with 2.6.36-rc3.

The first thing I tried was OpenSUSE 2.6.34 plus 19833b5dff.   This led me to
think it wasn't related to ASPM so I resorted to a bisect which ended up showing
it was 6f461f6c7c.

Anyways, all of the above is from vanilla 2.6.36-rc3 so lets ignore OpenSUSE
kernels.

http://ftp.suse.com/pub/people/tonyj/82573L/config  is the config for .36-rc3
generated using localmodconfig, defaults chosen for all prompts.

http://ftp.suse.com/pub/people/tonyj/82573L/dmesg  is the full dmesg

Tony
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