[edk2-devel] Multithreaded compression with LZMA2
Laszlo Ersek
lersek at redhat.com
Thu Dec 3 10:24:58 UTC 2020
On 12/02/20 03:59, Daniel Schaefer wrote:
> Hi everyone,
>
> I'm looking into how to speed up the build process and noticed that our
> build
> uses LZMA to encrypt the main firmware volume. Since it's quite big it
> takes a
> while but only uses one CPU thread.
>
> LZMA2 is a version of LZMA which can be multi-threaded and achieve much
> faster
> compression times. I did a quick benchmark using the `xz` command-line
> tool,
> which uses a modified version of the LZMA SDK that EDK2 uses. The
> results are:
>
> Uncompressed size: 64M
>
> | Algo | Comp Time | Decomp Time | Size | Threads |
> | ----- | --------- | ----------- | ---- | ------- |
> | LZMA | 19.67s | 0.9s | 9.1M | 1 |
> | LZMA2 | 20.11s | 1.2s | 9.2M | 1 |
> | LZMA2 | 8.31s | 1.0s | 9.4M | 4 |
>
> Using those commands:
>
> time xz --format=lzma testfile
> time unlzma testfile.lzma
>
> time xz --lzma2 testfile
> time unxz testfile.xz
>
> time xz -T4 --lzma2 testfile
> time unxz testfile.xz
>
> This is quite a significant improvement of build time, while
> decompression time
> and size only slightly increase. If that's a concern, then LZMA2 could
> be used
> for development only.
>
> I haven't investigated the details of how to support this in the code
> but it
> appears to be a simple change, since the LZMA SDK that we use already
> supports
> LZMA2.
>
> What do you think?
"xz -T" works by splitting the input into blocks, and it generates a
multi-block compressed output. I'm unsure if the current LZMA
decompressor that runs inside the firmware (= guided section extractor)
copes with multi-block input.
Thanks
Laszlo
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#68236): https://edk2.groups.io/g/devel/message/68236
Mute This Topic: https://groups.io/mt/78651832/1813853
Group Owner: devel+owner at edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [edk2-devel-archive at redhat.com]
-=-=-=-=-=-=-=-=-=-=-=-
More information about the edk2-devel-archive
mailing list