Date: Sun, 14 Jun 2015 19:46:05 +0100 From: Bruce Simpson <bms@fastmail.net> To: Steve Kargl <sgk@troutmask.apl.washington.edu> Cc: Slawa Olhovchenkov <slw@zxy.spb.ru>, Craig Rodrigues <rodrigc@FreeBSD.org>, Marcel Moolenaar <marcel@xcllnt.net>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, Marcel Moolenaar <marcel@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org> Subject: Re: svn commit: r284198 - head/bin/ls Message-ID: <557DCBED.2010804@fastmail.net> In-Reply-To: <20150614171031.GA5857@troutmask.apl.washington.edu> References: <201506100127.t5A1RdX6051959@svn.freebsd.org> <20150612204309.11dd3391@kan> <20150613024916.GA98218@troutmask.apl.washington.edu> <1434208622.1415.57.camel@freebsd.org> <C88CB169-12FE-4692-92AA-5C7D41BB61DF@FreeBSD.org> <557C661F.8080104@freebsd.org> <860017ED-D754-450C-865D-2D81A30C2212@xcllnt.net> <CAG=rPVd93Q18aYnSGSf_QH4C08RCq5wsdKQSNYTgWQ2huTbUHQ@mail.gmail.com> <20150614100045.GF58397@zxy.spb.ru> <557D55CB.5050009@fastmail.net> <20150614171031.GA5857@troutmask.apl.washington.edu>
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On 14/06/2015 18:10, Steve Kargl wrote: > On Sun, Jun 14, 2015 at 11:22:03AM +0100, Bruce Simpson wrote: >> >> But I have yet to see a coherent argument here -- size(1) numbers, RSS >> figures etc. -- about how it allegedly adds bloat. Most of what I've >> seen so far is POLA, NIH resistance, and hand-wavery. >> > > It is not alleged. I actaully measured the bloat libxo > caused when w(1) was converted. ... > Here's the bloat with ls(1) ... Steve, that's still less than one 4KB page. OK, so I find it difficult to believe -- in this day and age of pipeline-saving CMOV instructions -- that the overhead is as large as ~2800 bytes, where I would have expected roughly half that. But not knowing what compile options you used, or having information about sizes (and working sets - just listing file sizes is hand waving) across the libxo modified binaries, this still doesn't give a complete picture of the relative cost of the feature. However, that's still a very modest increase, considering the architectural scope of the libxo change and what it provides. Warner suggests that for some targets it is too much, and he might have a point. But if you look at That Other Operating System, this is generally dealt with there by deploying something like BusyBox instead. I can understand why we don't want to go down that road -- in my experience, the choice of BusyBox sacrifices too much usability -- and would support a WITH_LIBXO for that reason alone. The extra bytes might even disappear in the noise after crunchgen. I think it is also fair that the people who advocated for this in the beginning (not I, though I support it in principle) and did the work (not I either, ENOTIME) should have done this work up front. I've had to do it to justify similar changes in other projects.
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