No, I’m not going to criticise the ecompress implementation, actually I’m quite glad that ecompress was created, because it’s that, which allows what I’m going to write here 😉
So, on most modern systems, with the exception of servers and laptops, one of the problems you most rarely have is running out of disk space. Standard 3.5” SATA drives are cheap and so rarely you have to save disk space. So while I think it’s still a good default to compress manpages, info pages and documentation, most users don’t really need that.
So if you don’t mind using some more space for documentation and man pages, you might want to try this on your make.conf:
PORTAGE_COMPRESS=""
This way ecompress will be a no-op and will skip on compressing the doc, installing it non-comrpessed, using more space, but less (not much less, but still less) CPU time during build.
One nice advantage is that also displaying manpages will be faster as it doesn’t have to decompress them on the fly 😉 (and bzip2 can be quite slow to decompress even on modern computers, when compared to gzip).