How do I enable multi-threaded LZMA2 using 7-zip 9.20 on the command line? I know this is normally done with the -t option like so: "-tzip" .
How do I do this with LZMA2? I tried -tlzma and -tlzma2 and neither one works. I also tried not passing -t at all, and it just runs single threaded with "lzma" mode.
Here is the command I currently have, but it is slow, and single threaded:
"C:\Program Files\7-Zip\7z.exe" a -r -tzip -y XMLBackup.zip *.xml5 Answers
Try -m0=lzma2
"C:\Program Files\7-Zip\7z.exe" a -m0=lzma2 -r -y XMLBackup.zip *.xmlThe help file says it's mt=number_of_threads
I know this is specifically about the command line, but one thing I can say about when using the GUI, as soon as you switch to LMZA2 you got all the options. And it DOES speed up compression a great deal, utilizing the full 100% of your CPU's power rather than the usual 25%.
7z a -txz -mx=9 -mmt=on out.tar.xz in.tar-txz uses XZ (LZMA2)
-mx=9 sets the compression level (1 fastest / 9 best compression)
-mmt=on LZMA2 only supports up to 2 threads (either -mmt=on or -mmt=off) but multithreading is on by default
The multithreading mode is given in a -m flag, and it's apparently only implemented for zip, 7z, bzip2 and xz. More specifically, -mmt=<<# of threads>>. However, according to the documentation, it is enabled by default. See the CHM manual included with 7-zip for more information.
I tried a simple 7z command without multithrading options on a windows 2012 server with 2 cpu and both cpu are working hard to compress my big file, so I think multithreading is active by default.
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