Re: Plan for e100-e1000 in mainline

From: Steffen Persvold (sp@scali.com)
Date: Wed May 01 2002 - 09:19:53 EST


On Wed, 1 May 2002, Jeff Garzik wrote:

> J.A. Magallon wrote:
>
> >Hi.
> >
> >Well, subject says it all. Which is the status/plans for inclussion
> >of those drivers in mainline kernel ? AFAIR, e1000 had been licensed,
> >but e100 was not clear yet.
> >
>
> e100 has been in 2.5.x for quite a long time. All license issues have
> similarly been resolved a long time ago.
>
> I expect Intel's Q/A to green light their current driver. With a few
> patches it should be ready for 2.4.x soon.
>
> You can easily copy drivers/net/e100[0] into a 2.4.x kernel, it likely
> compiles without modification.
>

Has the latency issues with e100 compared to eepro100 been resolved too ?
Last time I checked the e100 driver (version 1.8.38) had terrible high
latency on small messages even in a back-to-back configuration (both
machines using the same driver). As a test I used netperf's TCP_RR
benchmark (TCP roundtrip) :

Message size | eepro100 latency (usec) | e100 latency (usec)
--------------------------------------------------------------
     16 108.985 114.116
     24 110.940 116.679
     32 114.129 119.608
     48 118.614 125.507
     64 124.341 1093.150
     96 135.864 1102.190
    128 147.177 1102.726
    192 167.343 838.799
    256 188.410 858.572
    384 230.797 900.941
    512 271.281 941.104
    768 354.270 1024.753
   1024 437.307 1108.231
   1536 612.688 1293.912
   2048 699.168 1334.828
   3072 872.554 1670.787
   4096 1032.183 1556.056

As you can see, with a TCP payload of 64 bytes the latency is quite high
with the e100 driver compared to the eepro100 driver. As a side note: it
didn't work well with the bonding module either (neither did the e1000
module).

Another funny thing is that the latency for the gigabit adapter (e1000)
is also higher than fast ethernet (eepro100) with small messages (<256
bytes) :

Message size | eepro100 latency (usec) | e1000 latency (usec)
--------------------------------------------------------------
     16 108.985 177.138
     24 110.940 177.370
     32 114.129 177.523
     48 118.614 178.189
     64 124.341 178.769
     96 135.864 179.669
    128 147.177 180.517
    192 167.343 183.339
    256 188.410 184.552
    384 230.797 188.929
    512 271.281 191.787
    768 354.270 198.745
   1024 437.307 205.793
   1536 612.688 240.772
   2048 699.168 249.540
   3072 872.554 282.348
   4096 1032.183 299.220

Regards,
 --
  Steffen Persvold | Scalable Linux Systems | Try out the world's best
 mailto:sp@scali.com | http://www.scali.com | performing MPI implementation:
Tel: (+47) 2262 8950 | Olaf Helsets vei 6 | - ScaMPI 1.13.8 -
Fax: (+47) 2262 8951 | N0621 Oslo, NORWAY | >320MBytes/s and <4uS latency

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