Date: Sat, 14 Dec 2013 22:44:10 +0100 From: Stefan Esser <se@freebsd.org> To: freebsd-current@freebsd.org Cc: kib@freebsd.org Subject: SVN commit 259045 breaks -CURRENT Message-ID: <52ACD12A.5020906@freebsd.org>
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I noticed a severe slowdown and network problems on my amd64 -CURRENT system. By bisecting SVN revisions I identified the following commit to be responsible: ---------------------------------------------------------------------- r259045 | kib | 2013-12-06 22:44:13 +0100 (Fri, 06 Dec 2013) | 9 lines Disallow optimizations which potentially remove boundary checks for signed values due to a compiler authors considering integer overflow as impossible. The change follows suit of other projects taking the same measure. ---------------------------------------------------------------------- This commit added the following line to /sys/conf/kern.mk: CFLAGS+= -fno-strict-overflow The most obvious symptoms of the problem on my system are: 1) sa-spamd needs > 140 seconds to start (instead of a few seconds) 2) SSH logins are very slow, many seconds of delay between connect and password prompt, several seconds after password entry until a command prompt appears (normally instantaneous) In general it takes many seconds to open a TCP socket, even to localhost. I can perform further tests on this system, but it will be a lot of work to locate the source files that are mis-compiled with -fno-strict-overflow. I'm surprised that nobody else seems to be affected by this problem, since it is very obvious on my system and clearly caused by the above mentioned commit. My kernel configuration is a stripped down GENERIC plus ZFS, IPFW and LINUX emulation. I can provide full details and a kernel that exposes the problem on request. Regards, STefan
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