Thanks, Nick!
On 9/13/19 4:24 PM, Nick Mathewson wrote: > On Fri, Sep 13, 2019 at 2:05 PM Steve Snyder <swsny...@snydernet.net> wrote: >> >> Given the multiple compression types supported (none, lzma, zlib, zstd), >> what is the order of preference for runtime use? >> >> Put another way, which compression method(s) should be supported to get >> optimal runtime performance from a Tor node? > > For big objects like consensuses or consensus diffs that are sent over > and over, relays prefer to use whichever compression method has the > highest compression -- that's lzma2, then zstd, then zlib, then none. > Lzma2 (aka xz) is more expensive to calculate, but the relays only > need to calculate it once per compressed object, and then they can > send it over and over. > > For smaller objects that are compressed in a stream (descriptors and > microdescriptors), relays will not use xz, since it would be to > expensive to recompute it for every stream. They'll prefer zstd, then > zlib, then none. > > So if you want to save bandwidth above all, you should enable all > compression algorithms. > > If you want to save CPU above all, you should enable all compression > algorithms except xz. > > If you want to save bandwidth and CPU, I _think_ that enabling all the > compression algorithms will result in Tor making good choices (as > described above). But I'd appreciate benchmarks if anybody has tried > it both ways to find out. > > cheers, > _______________________________________________ tor-dev mailing list tor-dev@lists.torproject.org https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-dev
