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Date:      Tue, 23 Aug 2016 11:05:47 +0300
From:      Toomas Soome <tsoome@me.com>
To:        Warner Losh <imp@bsdimp.com>
Cc:        Andriy Gapon <avg@freebsd.org>, Toomas Soome <tsoome@freebsd.org>, src-committers <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>
Subject:   Re: svn commit: r304321 - in head/sys: boot/efi/boot1 boot/efi/loader boot/i386/boot2 boot/i386/gptboot boot/i386/gptzfsboot boot/i386/zfsboot boot/userboot/ficl boot/userboot/userboot boot/userboot/zf...
Message-ID:  <1C479C8A-9F58-425C-8AC2-0A6809F39ACA@me.com>
In-Reply-To: <AE896F50-D053-4C30-BB43-286E1CCDE4B8@me.com>
References:  <201608180037.u7I0b77A095653@repo.freebsd.org> <7bdb0cf5-e139-375b-8be6-c1280e39da25@FreeBSD.org> <4c76efd6-146a-e70b-c065-729d223e3398@FreeBSD.org> <AE24A37C-51F5-4CEC-9399-D7FDEBC93972@me.com> <CANCZdfo0P7CPPf4khzj_JnSjWQ4gVqK9wSEqW=LCdZKQwGh6Sw@mail.gmail.com> <AE896F50-D053-4C30-BB43-286E1CCDE4B8@me.com>

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> On 22. aug 2016, at 17:56, Toomas Soome <tsoome@me.com> wrote:
>=20
>=20
>> On 22. aug 2016, at 17:19, Warner Losh <imp@bsdimp.com> wrote:
>>=20
>> On Mon, Aug 22, 2016 at 3:44 AM, Toomas Soome <tsoome@me.com> wrote:
>>> I do suspect the size difference there is partially due to ficl, in =
illumos (ficl 4):
>>>=20
>>> -rw-r--r--   1 tsoome   staff     132508 aug 22 09:18 libficl.a
>>>=20
>>> and freebsd (ficl 3):
>>>=20
>>> -rw-r--r--  1 root  wheel  213748 Aug 19 01:57 libficl.a
>>>=20
>>> so, there definitely is some space=E2=80=A6
>>=20
>> Same compiler? Clang bloats the boot code rather substantially, even =
after
>> all the flags to tell it to generate smaller code are used. gcc 4.2.x
>> built stuff
>> was substantially smaller.
>>=20
>> There's a 520kb limit enforced in the boot1 for similar reasons. =
Looks like
>> the combination of options makes us use just enough extra memory to
>> sink the battleship...
>>=20
>> Warner
>>=20
>=20
>=20
> Actually I only now realized I was comparing apples with oranges=E2=80=A6=
 I forgot the fbsd builds 32bit version in ficl32, this one is 64bit. =
and yes the 32bit version is not that big at all:D
>=20
> Also, after done some digging, I have found few instances of =
duplicated code (we can share sha2 with geli and so if sha512 is already =
needed, it will become another =E2=80=9Cfree lunch=E2=80=9D). Also, =
unless I=E2=80=99m mistaken, for some reason the bzip *compression* is =
brought in - correct me if I=E2=80=99m wrong, but afaik only =
decompression is needed=E2=80=A6
>=20
> So before going after =E2=80=9Cuseless features=E2=80=9D, there are =
some =E2=80=9Chidden=E2=80=9D resources to remove extra fat.
>=20

I did some more digging. while ld has =E2=80=94gc-sections to clean up =
unused bits, to make it effective, the code build does also need -Os =
-fdata-sections -ffunction-sections.
So I did just very simple test by adding those flags to bsd.stand.mk =
and:

first the =E2=80=9Cdefault=E2=80=9D binaries from /boot:
-r-xr-xr-x  1 root  wheel  446464 Aug 19 08:46 /boot/zfsloader
-rw-r--r--  1 root  wheel  438272 Aug 23 00:30 /boot/zfsloader.b
-r-xr-xr-x  1 root  wheel  446464 Aug  5 08:37 /boot/zfsloader.old
-r--r--r--  1 root  wheel  406568 Aug 19 08:46 /boot/userboot.so

(note, zfsloader.b here is built with https://reviews.freebsd.org/D7600)

now after adding compile flags  -Os -fdata-sections -ffunction-sections:

-rw-r--r--  1 root  wheel  389120 Aug 23 10:12 zfsloader
-rwxr-xr-x  1 root  wheel  378156 Aug 23 10:12 zfsloader.bin
-rwxr-xr-x  1 root  wheel  437514 Aug 23 10:12 zfsloader.sym
-rwxr-xr-x  1 root  wheel  375912 Aug 23 10:03 userboot.so

and finally test for Andriy with:
LOADER_BZIP2_SUPPORT=3Dyes
LOADER_FIREWIRE_SUPPORT=3Dyes

-rw-r--r--  1 root  wheel  421888 Aug 23 10:22 zfsloader
-rwxr-xr-x  1 root  wheel  409932 Aug 23 10:22 zfsloader.bin
-rwxr-xr-x  1 root  wheel  472021 Aug 23 10:22 zfsloader.sym
-rwxr-xr-x  1 root  wheel  375912 Aug 23 10:22 userboot.so

note the userboot.so did not change from those flags.

This is just an result from compile, and by adding 3 options to =
bsd.stand.mk; however, not all Makefiles in loader tree seem to include =
it, and most importantly, haven=E2=80=99t tested real boot yet;)

To conclude, some more work is needed to review the Makefiles, build =
options used etc, also I don=E2=80=99t know all the background why the =
compiler options are set as they currently are - were there any related =
compiler/linker bugs, or any other reasons, also how/if other platforms =
are affected - for example bsd.stand.mk does set -Os for pc98, but not =
for others=E2=80=A6

rgds,
toomas=



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