On Sat Dec 24 11, Bruce Evans wrote:
> On Fri, 23 Dec 2011, Adrian Chadd wrote:
>
> >Well, the whole kernel is bloated at the moment, sorry.
> >
> >I've been trying to build the _bare minimum_ required to bootstrap
> >-HEAD on these embedded boards and I can't get the kernel down below 5
> >megabytes - ie, one with FFS (with options disabled), MIPS, INET (no
> >INET6), net80211, ath (which admittedly is big, but I need it no
> >matter what, right?) comes in at:
> >
> >-r-xr-xr-x 1 root wheel 5307021 Nov 29 19:14 kernel.LSSR71
> >
> >And with INET6, on another board (and this includes MSDOS and the
> >relevant geom modules):
> >
> >-r-xr-xr-x 1 root wheel 5916759 Nov 28 12:00 kernel.RSPRO
> >
> >.. honestly, that's what should be addressed. That's honestly a bit
> >ridiculous.
>
> It's disgusting, but what problems does it cause apart from minor slowness
> from cache misses?
>
> I used to monitor the size of a minimal i386 kernel:
>
> % machine i386
> % cpu I686_CPU
> % ident MIN
> % options SCHED_4BSD
>
> In FreeBSD-5-CURRENT between 5.1R and 5.2R, this had size:
>
> text data bss dec hex filename
> 931241 86524 62356 1080121 107b39 /sysc/i386/compile/min/kernel
>
> A minimal kernel is not useful, but maybe you can add some i/o to it
> without bloating it too much.
>
> This almost builds in -current too. I had to add the following:
> - NO_MODULES to de-bloat the compile time
> - MK_CTF=no to build -current on FreeBSD.9. The kernel .mk files are
> still broken (depend on nonstandard/new features in sys.mk).
strange. the build(7) man page claims that:
"
WITH_CTF If defined, the build process will run the DTrace CTF
conversion tools on built objects. Please note that
this WITH_ option is handled differently than all other
WITH_ options (there is no WITHOUT_CTF, or correspond-
ing MK_CTF in the build system).
"
... so setting MK_CTF to anything shouldn't have (according to the man page).
cheers.
alex
> - comment out a line in if.c that refers to Vloif. if.c is standard
> but the loop device is optional.
>
> A few more changes to remove non-minimalities that are not defaults
> made little difference:
>
> % machine i386
> % cpu I686_CPU
> % ident MIN
> % options SCHED_4BSD
> %
> % # XXX kill default misconfigurations.
> % makeoptions NO_MODULES=yes
> % makeoptions COPTFLAGS="-O -pipe"
> %
> % # XXX from here on is to try to kill everything in DEFAULTS.
> %
> % # nodevice isa # needed for DELAY...
> % # nooptions ISAPNP # needed ...
> %
> % nodevice npx
> %
> % nodevice mem
> % nodevice io
> %
> % nodevice uart_ns8250
> %
> % nooptions GEOM_PART_BSD
> % nooptions GEOM_PART_EBR
> % nooptions GEOM_PART_EBR_COMPAT
> % nooptions GEOM_PART_MBR
> %
> % # nooptions NATIVE # needed ...
> % # nodevice atpic # needed ...
> %
> % nooptions NEW_PCIB
> %
> % nooptions VFS_ALLOW_NONMPSAFE
>
> text data bss dec hex filename
> 1663902 110632 136892 1911426 1d2a82 kernel
>
> (This was about 100K larger with -O2 and all DEFAULTS). The bloat since
> FreeBSD-5 is only 70%.
>
> Here are some sizes for my standard kernel (on i386). The newer
> versions have about the same number of features since they don't support
> so many old isa devices or so many NICs:
>
> text data bss dec hex filename
> 1483269 106972 172524 1762765 1ae5cd FreeBSD-3/kernel
> 1917408 157472 194228 2269108 229fb4 FreeBSD-4/kernel
> 2604498 198948 237720 3041166 2e678e FreeBSD-5.1.5/kernel
> 2833842 206856 242936 3283634 321ab2
> FreeBSD-5.1.5/kernel-with-acpi
> 2887573 192456 288696 3368725 336715 FreeBSD-5.1.5/kernel
> with my changes, -O2 and usb
> added relative to the above
> 2582782 195756 298936 3077474 2ef562 previous, with some excessive
> inlining avoided, and without -O2,
> and with ipfilter
> 1998276 159436 137748 2295460 2306a4 kernel.4
> a more up to date and less hacked on
> FreeBSD-4
> 4365549 262656 209588 4837793 49d1a1 kernel.7
> 4406155 266496 496532 5169183 4ee01f kernel.7.invariants
> 3953248 242464 207252 4402964 432f14 kernel.7.noacpi
> 4418063 268288 240084 4926435 4b2be3 kernel.7.smp
> various fairly stock FreeBSD-7R
> kernels
> 3669544 262848 249712 4182104 3fd058 kernel.c
> 4174317 258240 540144 4972701 4be09d kernel.c.invariants
> 3964455 250656 249808 4464919 442117 kernel.c.noacpi
> 3213928 240160 240596 3694684 38605c kernel.c.noacpi-ule
> 4285040 268288 286160 4839488 49d840 kernel.c.smp
> current before FreeBSD-8R
> not all built at the same time or
> with the same options. The 20%
> bloat between kernel.c.noacpi.ule
> and kernel.c.noacpi is mainly
> from not killing the default of
> -O2.
> 4742714 315008 401692 5459414 534dd6 kernel.8
> 4816900 319200 1813916 6950016 6a0c80 kernel.8.invariants
> 4490209 304832 395260 5190301 4f329d kernel.8.noacpi
> 4795475 323680 475420 5594575 555dcf kernel.8.smp
> various fairly stock FreeBSD-8R
> kernels
> 4979632 287020 488404 5755056 57d0b0 kernel.cur
> 5062953 289196 1902676 7254825 6eb329 kernel.cur.invariants
> 5361809 295052 576984 6233845 5f1ef5 kernel.cur.smp
>
> amd64 kernels are only bout 4% larger if i386 kernels are built with
> equivalant CFLAGS (-march=athlon64 for athlon64 CPU), but I usually
> optimize i386 kernels for space and portability by compiling them
> with -mtune=old.
>
> Bruce
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