By: Ricardo B (ricardo.b.delete@this.xxxxx.xx), May 13, 2013 6:13 am
Room: Moderated Discussions
Michael S (already5chosen.delete@this.yahoo.com) on May 13, 2013 3:50 am wrote:
> That's true for old (e.g. bzip2) implementations of compressors or for non-aggressive settings in new compressors.
> For new compressors/high effort blocks are up to GBs. It often makes big difference in practice.
> BTW, I just looked at 7zip installed on my work computer (v 9.20). It supports multiple threads
> when compressing to .zip by various methods, including LZMA. But when compressing to its native
> 7z format, which gives the best compression ratios, it only supports 2 threads.
>
Interesting.
My experience is a bit different, I see 7-zip use more than 2 threads.
Digging into it, the cause is that on Linux I use .xz, which defaults to LZMA2 and supports any number of threads, while you're using .7z, which defaults to LZMA and only supports 2 or 3 threads.
> That's true for old (e.g. bzip2) implementations of compressors or for non-aggressive settings in new compressors.
> For new compressors/high effort blocks are up to GBs. It often makes big difference in practice.
> BTW, I just looked at 7zip installed on my work computer (v 9.20). It supports multiple threads
> when compressing to .zip by various methods, including LZMA. But when compressing to its native
> 7z format, which gives the best compression ratios, it only supports 2 threads.
>
Interesting.
My experience is a bit different, I see 7-zip use more than 2 threads.
Digging into it, the cause is that on Linux I use .xz, which defaults to LZMA2 and supports any number of threads, while you're using .7z, which defaults to LZMA and only supports 2 or 3 threads.
