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Date:      Fri, 18 Apr 2003 18:58:07 +0200
From:      Borje Josefsson <bj@dc.luth.se>
To:        "Jin Guojun [NCS]" <j_guojun@lbl.gov>
Cc:        freebsd-performance@freebsd.org
Subject:   Re: patch for test (Was: tcp_output starving -- is due to mbuf  get delay?)
Message-ID:  <200304181658.h3IGw72F021961@dc.luth.se>
In-Reply-To: Your message of Thu, 17 Apr 2003 22:12:02 PDT. <3E9F8922.1166ABA8@lbl.gov> 

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On Thu, 17 Apr 2003 22:12:02 PDT "Jin Guojun [NCS]" wrote:

> I have modified the sockbuf and mbuf operation to double the throughput=
 over
> high bandwidth delay product path.
> =

> The patch is available at:
>     http://www-didc.lbl.gov/~jin/network/lion/content.html#FreeBSD_Patc=
hes
> =

> The current modification is for tcp transmission only.
> =

> I have adapted some code of uipc_socket2.c from Sam Leffler
>     http://www.freebsd.org/~sam/thorpe-stable.patch
> =

> for tcp receiver, but it has not been tested yet, so the tcp_input.p is=
 empty.
> =

> I ignored all record chain (m_nextpkt) related code. The details is exp=
lained at
> =

>     http://www-didc.lbl.gov/~jin/network/lion/content.html#BSDMbuf
> =

> Once the tcp_input code is tested, I will submit the patch to bugs@free=
bsd.org.
> I may submit the patch regardless if tcp_input code works or not, becau=
se the
> tcp
> sender (server) is more important in high-speed network than the receiv=
er
> (client).
> =

> It is appreciated if any one can verify the patch and provide feedback.=


OK. I have now tried this patch on a newly-installed 4.8R. The patch =

applied fine. When the sysctl net.inet.tcp.liondmask is unset, everything=
 =

seems OK, but when setting it to 7 (as specified with the patch =

instructions) i get:

  Fatal trap 12: page fault while in kernel mode.
  (I could write down all the stuff on addresses etc if it makes sense)

when I run ttcp to test the performance.

This is repeatable.

I'm willing to test more, if someone provides me with some hints on what =

to do.

--B=F6rje



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