One of the principal reasons jumbo frames have not been standardized is due to latency concerns. I assume this group can appreciate the IEEE holding ground on this. For a short time, servers with gigabit NICs suffered but smarter NICs were developed (TSO, LRO, other TLAs) and OSs upgraded to support them and I believe it is no longer a significant issue.
Kevin Gross On Thu, May 12, 2011 at 10:31 AM, Fred Baker <[email protected]> wrote: > > On May 9, 2011, at 11:06 AM, Rick Jones wrote: > > > GSO/TSO can be thought of as a symptom of standards bodies (eg the IEEE) > > refusing to standardize an increase in frame sizes. Put another way, > > they are a "poor man's jumbo frames." > > I'll agree, but only half; once the packets are transferred on the local > wire, any jumbo-ness is lost. GSO/TSO mostly squeezes interframe gaps out of > the wire and perhaps limits the amount of work the driver has to do. The > real value of an end to end (IP) jumbo frame is that the receiving system > experiences less interrupt load - a 9K frame replaces half a dozen 1500 byte > frames, and as a result the receiver experiences 1/5 or 1/6 of the > interrupts. Given that it has to save state, activate the kernel thread, and > at least enqueue and perhaps acknowledge the received message, reducing > interrupt load on the receiver makes it far more effective. This has the > greatest effect on multi-gigabit file transfers. > _______________________________________________ > Bloat mailing list > [email protected] > https://lists.bufferbloat.net/listinfo/bloat >
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