Re: [PATCH v1 0/2] Introduce the initify gcc plugin

Emese Revfy
2016-06-28T20:23:14Z

On Tue, 28 Jun 2016 19:00:22 +0200
Mathias Krause <minipli@ld-linux.so> wrote:

> > section vanilla vanilla + initify change
> > -----------------------------------------------------------------------
> > .rodata 39059688 (0x25400e8) 38527210 (0x24be0ea) -532478
> > .data 45744128 (0x2ba0000) 45404160 (0x2b4d000) -339968
> > .init.data 1361144 (0x14c4f8) 1674200 (0x198bd8) +313056
> > .text 77615128 (0x4a05018) 77576664 (0x49fb9d8) -38464
> > .init.text 1108455 (0x10e9e7) 1137618 (0x115bd2) +29163
>
> You should probably provide numbers for .init.rodata.str, .exit.rodata.str
> and .exit.text as well. Otherwise this delta calculation suggests a rather
> gigantic image size reduction which is probably not the case ;)

init.rodata.str is an input section that merges into the INIT_DATA output section.
I didn't make statistics for exit* yet because I have a problem with that (I asked
for help in a previous e-mail).

> Also a comparison of the final kernel image size would be nice to see if

I no longer have the vmlinux images but I saved away the readelf outputs,
here's the PT_LOAD size data:

FileSiz (vanilla) FileSiz (vanilla+initify) change
-----------------------------------------------------------------------
00 119189504 (0x71ab000) 118657024 (0x7129000) -532480
01 45838336 (0x2bb7000) 45498368 (0x2b64000) -339968
03 2830336 (0x2b3000) 3198976 (0x30d000) +368640

00 .text .text.exit .text.startup .notes __ex_table .rodata __bug_table .pci_fixup
.builtin_fw .tracedata __ksymtab __ksymtab_gpl __ksymtab_strings __init_rodata __param __modver
01 .data .fini_array .vvar
03 .init.text .altinstr_aux .init.data .x86_cpu_dev.init .parainstructions .altinstructions
.altinstr_replacement .iommu_table .apicdrivers .exit.text .exit.data .smp_locks .bss .brk

I think the smaller .data section is wrong, so I'll look into it.

--
Emese