82557/8/9 Ethernet Pro 100 interrupt mitigation support

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Hello everyone,

I have several systems with three integrated Intel 82559 (I *think*).

Does someone know if these boards support hardware interrupt mitigation? I.e. is it possible to configure them to raise an IRQ only if their hardware buffer is full OR if some given time (say 1 ms) has passed and packets are available in their hardware buffer.

I've been using the eepro100 driver up to now, but I'm about to try the e100 driver. Would I have to use NAPI? Or is this an orthogonal feature?

Regards.

00:08.0 Ethernet controller: Intel Corporation 82557/8/9 Ethernet Pro 100 (rev 08)
Subsystem: Intel Corporation EtherExpress PRO/100B (TX)
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
Latency: 32 (2000ns min, 14000ns max), Cache Line Size: 32 bytes
Interrupt: pin A routed to IRQ 10
Region 0: Memory at e6400000 (32-bit, non-prefetchable) [size=4K]
Region 1: I/O ports at d800 [size=64]
Region 2: Memory at e6100000 (32-bit, non-prefetchable) [size=1M]
Capabilities: [dc] Power Management version 2
Flags: PMEClk- DSI+ D1+ D2+ AuxCurrent=0mA PME(D0+,D1+,D2+,D3hot+,D3cold+)
Status: D0 PME-Enable- DSel=0 DScale=2 PME-

00:09.0 Ethernet controller: Intel Corporation 82557/8/9 Ethernet Pro 100 (rev 08)
Subsystem: Intel Corporation EtherExpress PRO/100B (TX)
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
Latency: 32 (2000ns min, 14000ns max), Cache Line Size: 32 bytes
Interrupt: pin A routed to IRQ 11
Region 0: Memory at e6403000 (32-bit, non-prefetchable) [size=4K]
Region 1: I/O ports at dc00 [size=64]
Region 2: Memory at e6200000 (32-bit, non-prefetchable) [size=1M]
Capabilities: [dc] Power Management version 2
Flags: PMEClk- DSI+ D1+ D2+ AuxCurrent=0mA PME(D0+,D1+,D2+,D3hot+,D3cold+)
Status: D0 PME-Enable- DSel=0 DScale=2 PME-

00:0a.0 Ethernet controller: Intel Corporation 82557/8/9 Ethernet Pro 100 (rev 08)
Subsystem: Intel Corporation EtherExpress PRO/100B (TX)
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
Latency: 32 (2000ns min, 14000ns max), Cache Line Size: 32 bytes
Interrupt: pin A routed to IRQ 12
Region 0: Memory at e6402000 (32-bit, non-prefetchable) [size=4K]
Region 1: I/O ports at e000 [size=64]
Region 2: Memory at e6000000 (32-bit, non-prefetchable) [size=1M]
Capabilities: [dc] Power Management version 2
Flags: PMEClk- DSI+ D1+ D2+ AuxCurrent=0mA PME(D0+,D1+,D2+,D3hot+,D3cold+)
Status: D0 PME-Enable- DSel=0 DScale=2 PME-

Here is Intel's page for the 82559:
http://www.intel.com/design/network/products/lan/controllers/82559.htm

The "82559ER Fast Ethernet PCI Controller" data sheet mentions a 3 KB receive FIFO. I suppose that's too small to aggregate several frames?

The "8255x Controller Family Open Source Software Developer Manual" mentions the features supported by the 82559. I don't see anything related to interrupt mitigation support.

Does NAPI work well when there is no hardware interrupt mitigation support?

Regards.

82558/9 hardware does, sort of. But the e100 driver doesn't use it because it uses NAPI to minimize rx & tx interrupts.

Use NAPI. The e100 driver has been NAPI-only for a while.

James Chapman
Katalix Systems Ltd
http://www.katalix.com
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