Commit Graph

4 Commits

Author SHA1 Message Date
Luigi Rizzo
02ad408380 revise the implementation of the rings connected to the host stack 2011-12-05 15:21:21 +00:00
Luigi Rizzo
506cc70cce 1. Fix the handling of link reset while in netmap more.
A link reset now is completely transparent for the netmap client:
   even if the NIC resets its own ring (e.g. restarting from 0),
   the client will not see any change in the current rx/tx positions,
   because the driver will keep track of the offset between the two.

2. make the device-specific code more uniform across different drivers
   There were some inconsistencies in the implementation of the netmap
   support routines, now drivers have been aligned to a common
   code structure.

3. import netmap support for ixgbe . This is implemented as a very
   small patch for ixgbe.c (233 lines, 11 chunks, mostly comments:
   in total the patch has only 54 lines of new code) , as most of
   the code is in an external file sys/dev/netmap/ixgbe_netmap.h ,
   following some initial comments from Jack Vogel about making
   changes less intrusive.
   (Note, i have emailed Jack multiple times asking if he had
   comments on this structure of the code; i got no reply so
   i assume he is fine with it).

Support for other drivers (em, lem, re, igb) will come later.

"ixgbe" is now the reference driver for netmap support. Both the
external file (sys/dev/netmap/ixgbe_netmap.h) and the device-specific
patches (in sys/dev/ixgbe/ixgbe.c) are heavily commented and should
serve as a reference for other device drivers.

Tested on i386 and amd64 with the pkt-gen program in tools/tools/netmap,
the sender does 14.88 Mpps at 1050 Mhz and 14.2 Mpps at 900 MHz
on an i7-860 with 4 cores and 82599 card. Haven't tried yet more
aggressive optimizations such as adding 'prefetch' instructions
in the time-critical parts of the code.
2011-12-05 12:06:53 +00:00
Luigi Rizzo
85df379184 fix formatting warning using casts. The numbers involved
are small and these are debug statements, so there is no reason to
obfuscate the format string with PRIsomeKINDofINTEGER
2011-11-23 09:45:48 +00:00
Luigi Rizzo
68b8534bdf Bring in support for netmap, a framework for very efficient packet
I/O from userspace, capable of line rate at 10G, see

	http://info.iet.unipi.it/~luigi/netmap/

At this time I am bringing in only the generic code (sys/dev/netmap/
plus two headers under sys/net/), and some sample applications in
tools/tools/netmap. There is also a manpage in share/man/man4 [1]

In order to make use of the framework you need to build a kernel
with "device netmap", and patch individual drivers with the code
that you can find in

	sys/dev/netmap/head.diff

The file will go away as the relevant pieces are committed to
the various device drivers, which should happen in a few days
after talking to the driver maintainers.

Netmap support is available at the moment for Intel 10G and 1G
cards (ixgbe, em/lem/igb), and for the Realtek 1G card ("re").
I have partial patches for "bge" and am starting to work on "cxgbe".
Hopefully changes are trivial enough so interested third parties
can submit their patches. Interested people can contact me
for advice on how to add netmap support to specific devices.

CREDITS:
    Netmap has been developed by Luigi Rizzo and other collaborators
    at the Universita` di Pisa, and supported by EU project CHANGE
    (http://www.change-project.eu/)
    The code is distributed under a BSD Copyright.

[1] In my opinion is a bad idea to have all manpage in one directory.
  We should place kernel documentation in the same dir that contains
  the code, which would make it much simpler to keep doc and code
  in sync, reduce the clutter in share/man/ and incidentally is
  the policy used for all of userspace code.
  Makefiles and doc tools can be trivially adjusted to find the
  manpages in the relevant subdirs.
2011-11-17 12:17:39 +00:00