-------- Forwarded Message -------- Subject: Re: [tor-relays] Multi-core Support Date: Tue, 02 Jun 2015 11:55:31 -0400 From: 12xBTM 12xBTM@gmail.com To: Roman Mamedov rm@romanrm.net

Some multicore support (at least 4 cores) should be a priority. Going beyond doesn't cater to many node operators at this time. Don't quote me on the numbers, but having decent 4-core support would let someone run a node with the same bandwidth on an Atom/i5 that currently runs on one thread of a Xeon. Or, if someone has a Xeon, such as a collocation center, would let them fully utilize the processor they are paying for, which would be a good morale boost for node operators.

But, honestly, the very minimum that can be done to improve the situation (which I know is being worked on as of 0.2.7) is improving a 2-thread program, to further utilize 2 threads of a cpu. That way, we can get by with 2 processes on one 4-thread CPU, instead of being tempted to jumped to 4 processes.

On 2.6.15 11:31, Roman Mamedov wrote:

On Tue, 02 Jun 2015 11:13:13 -0400 12xBTM 12xbtm@gmail.com wrote:

...

Improving multi-core support can allow users to saturate high bandwidth connections with cheaper processors, less setup, and just more efficient deployment of high-capacity nodes in general. Improving multi-core support should be a major priority.

Sure but I doubt anyone contests that it's better to have multicore support, than to not have it. However that work doesn't get automatically done.

One quick and simple stop-gap alternative that I suggested some time ago would be to stop ignoring more than two relays per IP address.

With the IPv4 shortage and abundance of multi-core CPUs, raising that limit to let's say 4, would at least allow many people to run a Tor process per core on the same single IPv4 that they have (utilizing up to four cores, not just two).

Considering that Tor is already somewhat multi-threaded (each process can use up to "120-130%" CPU), that might be just enough in most circumstances, since true 6-8-core CPUs are rare, and what's seen more often beyond 4 cores is either Intel HT or AMD's "light" core technologies.

Of course the management (and memory) overhead of multiple processes is still there, so proper multi-core scaling is the ideal final goal.