On Fri, 22 Sep 2006 08:15:13 +0200 Rainer Baumann <[EMAIL PROTECTED]> wrote:
> Trace Control for Netem: Emulate network properties such as long range > dependency and self-similarity of cross-traffic. > > kernel space: > The delay, drop, duplication and corruption values are readout in user space > and sent to kernel space via configfs. The userspace process will "hang on > write" until the kernel needs new data. > > In order to have always packet action values ready to apply, there are two > buffers that hold these values. Packet action values can be read from one > buffer and the other buffer can be refilled with new values simultaneously. > The synchronization of "need more delay values" and "return from write" is > done with the use of wait queues. > > Having applied the delay value to a packet, the packet gets processed by the > original netem functions. > > Signed-off-by: Rainer Baumann <[EMAIL PROTECTED]> > > --- > > Patch for linux kernel 2.6.16.19: http://tcn.hypert.net/tcnKernel_procfs.patch I like the concept of the trace based delay stuff, it is just that the implementation needs more work. Style: * whitespace around operators, keywords etc * use /* for comments not // * indentation scripts/Lindent may help * accidental blank line changes introduced in patch as well * You don't really change Makefile Code: * now netem depends on CONFIG_PROC_FS * why not use a miscdevice (/dev/netem_trace?) instead of /proc * still has signal flow control to process. This is an awkward way to do flow control and I don't think it is safe. * hard coding MAX_FLOWS leads to scaling problems. Not all users will want to waste the memory, and what if there are more flows. Can't you figure out a way to allocate and scale flow buffers. -- Stephen Hemminger <[EMAIL PROTECTED]> - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
