netdev - Re: Socket buffer sizes with autotuning

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]

Message-ID: <d1c2719f0804281344h4b8c98b9w6d7d4d2cbcdee857@mail.gmail.com>
Date:	Mon, 28 Apr 2008 13:44:06 -0700
From:	"Jerry Chu" <hkchu@...gle.com>
To:	"John Heffner" <johnwheffner@...il.com>
Cc:	"David Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
	rick.jones2@...com
Subject: Re: Socket buffer sizes with autotuning

On Mon, Apr 28, 2008 at 12:21 PM, John Heffner <johnwheffner@...il.com> wrote:
>
> On Mon, Apr 28, 2008 at 11:30 AM, Jerry Chu <hkchu@...gle.com> wrote:
> >  Correct, but its counterpart doesn't exist in tcp_is_cwnd_limited(). So
> >  cwnd will continue to grow when left < cwnd/sysctl_tcp_tso_win_divisor,
> >  which can be very large when cwnd is large.
> >
> >  If I change tcp_tso_win_divisor to 0, cwnd max out at 695 rather than 1037,
> >  exactly off by 1/3. I tried to add the same check to tcp_is_cwnd_limited():
> >
> >  diff -c /tmp/tcp.h.old tcp.h
> >  *** /tmp/tcp.h.old      Mon Apr 28 11:00:44 2008
> >  --- tcp.h       Mon Apr 28 10:54:10 2008
> >  ***************
> >  *** 828,833 ****
> >  --- 828,835 ----
> >                 return 0;
> >
> >         left = tp->snd_cwnd - in_flight;
> >  +       if (left >= 65536)
> >  +               return 0;
> >         if (sysctl_tcp_tso_win_divisor)
> >                 return left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd;
> >         else
> >
> >  >
> >
> >  But it doesn't seem to help (cwnd still grows to 1037).
>
> Cwnd is in packets, not bytes.

Yes, of course.

>
> Try this series of patches, against net-next.

Ah, you already know about this problem. Yes it does the trick.

Jerry

>
>  -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