On 2002-03-07 16:45, Simon 'corecode' Schubert wrote:

> to everybody who doesn't believe that: it really generates bad code.
> i've been having severe problems with my tcp and udp stack lately (on a
> i586/mmx machine). guess what, -O2 resulted in code which >>sometimes<<
> generated bad tcp and/or udp checksums (depending on ip). i didn't
> investigate any further, but believe me: not being able to access some
> dns servers is a pain in the ass.

I've seen this too.  When I built both my kernel and userland with -O3,
problems accessing the Internet started.  When I tried to use tcpdump to
find out what went wrong, I saw that it reported *all* outgoing packets for
*some* hosts as invalid [0xffff].

The funny thing was that depending on which source/destination I used, it
would either work or fail.  For destinations that it failed once, it failed
all the time.  Since I could not verify both the userland and kernel
binaries, I chose to disable most optimizations and stick with -O :-)

Giorgos Keramidas                       FreeBSD Documentation Project
keramida@{freebsd.org,ceid.upatras.gr}  http://www.FreeBSD.org/docproj/

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