Date: Thu, 19 Jun 2014 09:58:51 -0600 From: Ian Lepore <ian@FreeBSD.org> To: Magnus Nilsson <magnus.nilsson@gmail.com> Cc: freebsd-arm <freebsd-arm@FreeBSD.org>, freebsd-embedded@FreeBSD.org Subject: Re: Strange slowdown of zlib. Message-ID: <1403193531.20883.269.camel@revolution.hippie.lan> In-Reply-To: <CAHWWKwM_ETrPGZ1fPc451Hn=iCVEb9Z7qj2X0HEz-znwuR_k=w@mail.gmail.com> References: <CAHWWKwM_ETrPGZ1fPc451Hn=iCVEb9Z7qj2X0HEz-znwuR_k=w@mail.gmail.com>
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On Thu, 2014-06-19 at 17:44 +0200, Magnus Nilsson wrote: > I have the strangest behaviour of zlib on FreeBSD 8.2 (ARM, but I don't > think it's necessarily an ARM specific issue). > Doing > # md5 /lib/libz.so.5 > or > # cp /lib/libz.so.5 /tmp/ > # export LD_LIBRARY_PATH=/tmp/ > slows down applications (I've tested bsdtar and gzip) using zlib to a crawl > on my system. > > In the later case, doing > # unset LD_LIBRARY_PATH > reverts the issue. > However, I haven't found any way to recover from the first case, apart from > rebooting - then the execution time is back to normal. > > Here is a log of what I describe above (first moving zlib, then doing the > md5): > # cp some2MBfile /tmp/ > # time gzip /tmp/some2MBfile > real 0m0.325s > user 0m0.284s > sys 0m0.037s > # rm /tmp/some2MBfile.gz > # cp /lib/libz.so.5 /tmp/ > # export LD_LIBRARY_PATH=/tmp/ > # cp some2MBfile /tmp/ > # time gzip /tmp/some2MBfile > real 0m11.949s > user 0m11.635s > sys 0m0.035s > # rm /tmp/some2MBfile.gz > # unset LD_LIBRARY_PATH > # cp some2MBfile /tmp/ > # time gzip /tmp/some2MBfile > real 0m0.325s > user 0m0.288s > sys 0m0.035s > # rm /tmp/some2MBfile.gz > # md5 /lib/libz.so.5 > # cp some2MBfile /tmp/ > # time gzip /tmp/some2MBfile > real 0m11.919s > user 0m11.608s > sys 0m0.031s > # rm /tmp/some2MBfile.gz > > Do you have any idea what could be going on? > Any clues are welcome. > > Kind regards/Magnus This is a known problem on armv4/v5 in freebsd 8. Here is some archived info on it including patches that work around the problem (rather crudely, but good enough for our needs at $work). http://lists.freebsd.org/pipermail/freebsd-arm/2012-January/003288.html -- Ian
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