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review.coreboot.org / coreboot / d91f3a4eaf7f8399db83a9c2d5cba2452fefaf7a
commitd91f3a4eaf7f8399db83a9c2d5cba2452fefaf7a[log] [tgz]
authorZheng Bao <fishbaozi@gmail.com>Wed Aug 03 17:57:47 2022 +0800
committerMartin L Roth <gaumless@gmail.com>Wed Oct 12 16:55:58 2022 +0000
treefa32b8e3be93cf9c60bfa78e1f9f233c429d2d5d
parentdc522d22023a7ceb622e1f866a9a71c79343ae2c [diff]
lib/lzma: Build the source for decompression with flag -Ofast

The decompression is critical for speed of boot. So we sacrifice some
generated code size to optimize for speed.
This change speeds up the LZMA decompression between 3% and 6% at a
cost of just over 2k of additional code space.

BUG=b:223985641
TEST=Majolica

The test is done on Majolica and the result is listed below.

Time saved:
We tested the boot time with each flag for 10 times. The duration of
each decompression process is listed as below.
        Load FSP-M    Load ramstage  Load payload
        Ofast Os      Ofast Os       Ofast Os
        ------------------------------------------
        62543 62959   20585 22458    9945  10626
        62548 62967   20587 22461    9951  10637
        62560 62980   20588 22478    9951  10641
        62561 62988   20596 22478    9954  10643
        62569 62993   20596 22479    9954  10643
        62574 63000   20605 22492    9958  10647
        62575 63026   20615 22495    9959  10647
        62576 63038   20743 22614    9960  10647
        62587 63044   20758 22625    9961  10647
        62592 63045   20769 22637    9961  10647
        -----------------------------------------
average 62568 63004   20644 22521    9955  10642
                             (unit: microseconds)

Size sacrificed:
The size of object file with -Os:
  ./build/ramstage/lib/lzmadecode.o:     file format elf32-i386
    4 .text.LzmaDecode 00000d84  00000000  00000000  00000076  2**0
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
The size of object file with -Ofast:
  ./build/ramstage/lib/lzmadecode.o:     file format elf32-i386
    4 .text.LzmaDecode 00001719  00000000  00000000  00000080  2**4
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
(Output by running "objdump -h ./build/ramstage/lib/lzmadecode.o")

We can see that size is increased from 3460 bytes to 5913 bytes, a
change of 2453 bytes or 171%.

Change-Id: Ie003164e2e93ba8ed3ccd207f3af31c6acf1c5e2
Signed-off-by: Zheng Bao <fishbaozi@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66392
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
2 files changed
tree: fa32b8e3be93cf9c60bfa78e1f9f233c429d2d5d
  1. 3rdparty/
  2. configs/
  3. Documentation/
  4. LICENSES/
  5. payloads/
  6. spd/
  7. src/
  8. tests/
  9. util/
  10. .checkpatch.conf
  11. .clang-format
  12. .editorconfig
  13. .gitignore
  14. .gitmodules
  15. .gitreview
  16. .mailmap
  17. AUTHORS
  18. COPYING
  19. gnat.adc
  20. MAINTAINERS
  21. Makefile
  22. Makefile.inc
  23. README.md
  24. toolchain.inc
README.md

coreboot README

coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload.

With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required.

coreboot was formerly known as LinuxBIOS.

Payloads

After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot.

See https://www.coreboot.org/Payloads for a list of supported payloads.

Supported Hardware

coreboot supports a wide range of chipsets, devices, and mainboards.

For details please consult:

Build Requirements

  • make
  • gcc / g++ Because Linux distribution compilers tend to use lots of patches. coreboot does lots of "unusual" things in its build system, some of which break due to those patches, sometimes by gcc aborting, sometimes - and that's worse - by generating broken object code. Two options: use our toolchain (eg. make crosstools-i386) or enable the ANY_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this case).
  • iasl (for targets with ACPI support)
  • pkg-config
  • libssl-dev (openssl)

Optional:

  • gdb (for better debugging facilities on some targets)
  • ncurses (for make menuconfig and make nconfig)
  • flex and bison (for regenerating parsers)

Building coreboot

Please consult https://www.coreboot.org/Build_HOWTO for details.

Testing coreboot Without Modifying Your Hardware

If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU.

Please see https://www.coreboot.org/QEMU for details.

Website and Mailing List

Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website:

https://www.coreboot.org

You can contact us directly on the coreboot mailing list:

https://www.coreboot.org/Mailinglist

Copyright and License

The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details.

coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details.

This makes the resulting coreboot images licensed under the GPL, version 2.