On Mon, 28 May 2007 13:27:03 +0300 (EEST) "Ilpo Järvinen" <[EMAIL PROTECTED]> wrote:
> On Sun, 27 May 2007, Ilpo Järvinen wrote: > > > On Sun, 27 May 2007, Baruch Even wrote: > > > > > * Ilpo J?rvinen <[EMAIL PROTECTED]> [070527 14:16]: > > > > > > > > Thus, my original question basically culminates in this: should cc > > > > modules be passed number of packets acked or number of skbs acked? > > > > ...The latter makes no sense to me unless the value is intented to > > > > be interpreted as number of timestamps acked or something along those > > > > lines. ...I briefly tried looking up for documentation for cc module > > > > interface but didn't find anything useful about this, and thus asked in > > > > the first place... > > > > > > At least the htcp module that I wrote assumes that the number is actual > > > number of tcp packets so GSO should be considered. > > > > Thanks for the info! It is what I suspected... ...I'll write a patch for > > it tomorrow against net-2.6... Dave, beware that it will partially > > overlap with the changes made in the patch 8, so you might choose to put > > the patch 8 on hold until this issue is first resolved... > > > > > The consequences of this bug are not too large but it does make all > > > congestion control algorithms a lot less aggressive. On my machines GSO > > > is disabled by default (e1000 at 100mbps & Tigon3 @ 1Gbps). > > > > Agreed, that's my impression too. However, some algorithms do things > > like > 0 checks for it, so it might disturb their dynamics even more > > than in the "too small value" cases... > > Hmm, there seems to be another case that I'm not too sure of... > Please check the alternative I choose for SYN handling below... > > ...hmm... While exploring this SYN thingie, I noticed that commit > 164891aadf1721fca4dce473bb0e0998181537c6 drops !FLAG_RETRANS_DATA_ACKED > check from rtt_sample call (when combining it with pkts_acked call). > I hope that's intentional?!? ...the commit message didn't say anything > about it nor was anything in cc modules changed to accomodate that. > > > [PATCH] [TCP]: Fix GSO ignorance of pkts_acked arg (cong.cntrl modules) > > The code used to ignore GSO completely, passing either way too > small or zero pkts_acked when GSO skb or part of it got ACKed. > In addition, there is no need to calculate the value in the loop > but simple arithmetics after the loop is sufficient. Yes, thanks for fixing this. Wonder how it affects measurements. > It is not very clear how SYN segments should be handled, so I > choose to follow the previous implementation in this respect. Since we don't invoke congestion control modules until after the SYN handshake this is not a problem. -- 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
