svn commit: r284198 - head/bin/ls
Bruce Simpson
bms at fastmail.net
Sun Jun 14 18:46:10 UTC 2015
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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