Attention is currently required from: Jason Nien, Martin Roth.
Hello Martin Roth,
I'd like you to do a code review. Please visit
https://review.coreboot.org/c/coreboot/+/71675
to review the following change.
Change subject: mb/google/skyrim: Switch from LZMA to LZ4 compression for ramstage ......................................................................
mb/google/skyrim: Switch from LZMA to LZ4 compression for ramstage
Because skyrim is loading ramstage from SPI with the DMA engine, the size of the compressed image is less important to load speed than decompression time.
Because the LZ4 decompression is so much faster than LZMA, compressing with LZ4 saves us roughly 30ms in boot time.
For size, we're spending roughly 57KiB: fallback/ramstage 0x9b00 stage 130864 LZMA (305316 decompressed) fallback/ramstage 0x9b00 stage 189126 LZ4 (305316 decompressed)
Right now we have 2MiB empty space in Skyrim's RO before this change, and roughly 550KiB empty space in RW, so there aren't currently any size worries.
Just for fun, I also tested uncompressed ramstage, and it was still 18ms faster than LZMA, but that makes it roughly 12ms slower than LZ4.
BUG=b:264409477 TEST=Boot skyrim, look at boot speed.
Signed-off-by: Martin Roth martin.roth@amd.corp-partner.google.com Change-Id: Iedde6fc2db9d702c0ff2b0081e7baa254ac6699f --- M src/mainboard/google/skyrim/Kconfig 1 file changed, 32 insertions(+), 0 deletions(-)
git pull ssh://review.coreboot.org:29418/coreboot refs/changes/75/71675/1
diff --git a/src/mainboard/google/skyrim/Kconfig b/src/mainboard/google/skyrim/Kconfig index 493ecb5..94659db 100644 --- a/src/mainboard/google/skyrim/Kconfig +++ b/src/mainboard/google/skyrim/Kconfig @@ -37,6 +37,7 @@ select I2C_TPM select MAINBOARD_HAS_CHROMEOS select MAINBOARD_HAS_TPM2 + select MB_COMPRESS_RAMSTAGE_LZ4 select SOC_AMD_MENDOCINO select SOC_AMD_COMMON_BLOCK_I2C3_TPM_SHARED_WITH_PSP select SOC_AMD_COMMON_BLOCK_USE_ESPI