Date: Tue, 24 Jun 2014 00:44:27 +0200 From: Magnus Nilsson <magnus.nilsson@gmail.com> To: John-Mark Gurney <jmg@funkthat.com>, freebsd-embedded@freebsd.org, freebsd-arm <freebsd-arm@freebsd.org> Cc: Ian Lepore <ian@freebsd.org> Subject: Re: Strange slowdown of zlib. Message-ID: <CAHWWKwPS0LtvS1JXvug6DVYJuNH73h3ffZwGT25ffGyd4AEc7A@mail.gmail.com> In-Reply-To: <20140621140300.GO31367@funkthat.com> References: <CAHWWKwM_ETrPGZ1fPc451Hn=iCVEb9Z7qj2X0HEz-znwuR_k=w@mail.gmail.com> <1403193531.20883.269.camel@revolution.hippie.lan> <CAHWWKwNovBV7JouzquNK7kvw66ao9OtJ0uiQEsaftQa%2BDpbT5Q@mail.gmail.com> <20140621140300.GO31367@funkthat.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sat, Jun 21, 2014 at 4:03 PM, John-Mark Gurney <jmg@funkthat.com> wrote: > Magnus Nilsson wrote this message on Sat, Jun 21, 2014 at 14:13 +0200: >> While e.g. cat or md5 of an executable affects its speed, e.g. cp does not. >> Could there be some read access that's unaffected by your patches? > > I believe that cp uses mmap instead of the read syscall like cat and > md5... So this may be the case... > > -- > John-Mark Gurney Voice: +1 415 225 5579 > > "All that I will do, has been done, All that I have, has not." mmap() seems unaffected, well spotted. Not sure if it would be reasonable to use that fact for a workaround? I've done more patching and testing. Mark Tinguely's conservative, unofficial patch http://lists.freebsd.org/pipermail/freebsd-arm/2010-November/002635.html does not fix the issue. Grzegorz Bernacki's proof-of-concept patch http://lists.freebsd.org/pipermail/freebsd-arm/2010-March/002270.html /does/ fix the issue! But what's the potential downside? Debugging issues, as suggested in http://lists.freebsd.org/pipermail/freebsd-arm/2010-March/002290.html ? Performance issues? Something worse? I've looked at later releases (9.3) for backporting, but can't find anything that that handles PVF_EXEC as a special case like Mark and Grzegorz.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAHWWKwPS0LtvS1JXvug6DVYJuNH73h3ffZwGT25ffGyd4AEc7A>