Date: Thu, 31 Jul 2014 13:01:51 +0800 From: Julian Elischer <julian@freebsd.org> To: Pedro Giffuni <pfg@freebsd.org>, Shawn Webb <lattera@gmail.com> Cc: PaX Team <pageexec@freemail.hu>, freebsd-arch@freebsd.org, Bryan Drewery <bdrewery@FreeBSD.org>, Robert Watson <rwatson@FreeBSD.org>, Oliver Pinter <oliver.pntr@gmail.com> Subject: Re: [RFC] ASLR Whitepaper and Candidate Final Patch Message-ID: <53D9CDBF.6030003@freebsd.org> In-Reply-To: <112E989D-607B-47AC-8942-0FB049DA6C3D@freebsd.org> References: <96C72773-3239-427E-A90B-D05FF0F5B782@freebsd.org> <20140720201858.GB29618@pwnie.vrt.sourcefire.com> <alpine.BSF.2.11.1407230017490.88645@fledge.watson.org> <20140723004543.GH29618@pwnie.vrt.sourcefire.com> <20140724175704.GT29618@pwnie.vrt.sourcefire.com> <112E989D-607B-47AC-8942-0FB049DA6C3D@freebsd.org>
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On 7/31/14, 11:00 AM, Pedro Giffuni wrote: > Il giorno 24/lug/2014, alle ore 12:57, Shawn Webb <lattera@gmail.com> ha scritto: > >> >> The unixbench results are in. The overall scores are below. >> >> ASLR Disabled: 456.33 >> ASLR Enabled: 357.05 >> No ASLR: 474.03 is bigger better or worse? >> >> I've uploaded the raw results to >> http://0xfeedface.org/~shawn/aslr/2014-07-24_benchmark.tar.gz >> >> Take these results with a grain of salt, given that some of unixbench's >> test are filesystem-related and I'm running ZFS on an old laptop with >> little RAM. It does show that there is a performance impact when ASLR is >> enabled. and even from being included. I don't believe that should be forgotten. 1% here ,2% there.. soon you have lost noticeable performance. > The effect of the available RAM and/or age of the system is > independent of ASLR being on or off si I think the results are valid. > > As Robert said, the particularly bad result is the effect of having ASLR > disabled vs not having the patch at all. The priority should certainly be > to fix this. > > The effect of ASLR seems significant, I did expect it less but it is something > that can be expected. People that enable ASLR have to be aware that there > are consequences performance-wise. A further effect that hasn’t been quantified > but could be obtained from the raw data is the standard deviation. I would expect > that the randomization induced from using ASLR will cause an important increase > in the standard deviation and that performance will be basically unpredictable. > > The last issue is a show stopper from enabling ASLR by default but the first > issue is a show stopper from committing the patch at all :(. > > Of course, all just IMHO. > > Pedro. > > _______________________________________________ > freebsd-arch@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-arch > To unsubscribe, send any mail to "freebsd-arch-unsubscribe@freebsd.org" > > >
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