Sebastian Moeller <[email protected]> writes: >> On May 2, 2018, at 17:11, Toke Høiland-Jørgensen <[email protected]> wrote: >> >> + /* The last segment may be shorter; we ignore this, which means >> + * that we will over-estimate the size of the whole GSO segment >> + * by the difference in size. This is conservative, so we live >> + * with that to avoid the complexity of dealing with it. >> + */ >> + len = shinfo->gso_size + hdr_len; >> + } > > > Hi Toke, > > so I am on the fence with this one, as the extreme case is having a > super packet consisting out of 1 full-MTU packet plus a tiny leftover > in that case we pay a 50% bandwidth sacrifice which seems a bit high. > Nowm I have no real feling how likely this full MTU plus 64 byte > packet issue is in real life, but in the past I often saw maximum > packetsizes of around 3K bytes on my router indicating that having a > sup packet consisting just out of two segments might not be that rare. > So is there an easy way for me to measure the probability of seeing > that issue? > > I am all for sacrificing some bandwidth for better latency under load, > but few users will be happy with a 50% loss of bandwidth...
Well, in most cases such GSO segments will be split anyway (we split if <= 1 Gbps). So this inaccuracy will only hit someone who enables the shaper *and sets it to a rate rate > 1Gbps*. Which is not a deployment mode we have seen a lot of, I think? But sure, in principle you are right; I have no idea how to measure the probability, though. We could conceivably add another statistic, but, well, not sure it's worth it... I am certainly not going to do it ;) -Toke _______________________________________________ Cake mailing list [email protected] https://lists.bufferbloat.net/listinfo/cake
