netdev - Re: RE: A Linux TCP SACK Question

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 15 Apr 2008 10:01:25 -0700
From:	"John Heffner" <johnwheffner@...il.com>
To:	"Wenji Wu" <wenji@...l.gov>
Cc:	"Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi>,
	Netdev <netdev@...r.kernel.org>
Subject: Re: RE: A Linux TCP SACK Question

On Tue, Apr 15, 2008 at 9:39 AM, Wenji Wu <wenji@...l.gov> wrote:
>  SlowStart            0
>  CongAvoid            0
>  CongestionSignals    3
>  OtherReductions      13166
>  X_OtherReductionsCV  0
>  X_OtherReductionsCM  13166
>  CongestionOverCount  37
>  CurCwnd              10136
>
> MaxCwnd              173760
>  CurSsthresh          94894680
>  LimCwnd              4294965848
>  MaxSsthresh          94894680
>  MinSsthresh          46336

We can see that in both cases you are getting throttled by
tcp_moderate_cwnd (X_OtherReductionsCM).  I'm not sure offhand why
it's reaching this code - I would have thought that the high
tp->reordering would prevent this.  Ilpo, do you have any insights?

It's not all that surprising that packets_in_flight is a higher value
with newreno than sack, which would explain the higher window with
newreno.

Wenji, the web100 kernel has a sysctl - WAD_MaxBurst.  I suspect it
may make a significant difference if you set this to a large value.

  -John
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html