It was my impression from reading some older documents that tor didn't multithread well. Its also been my observation, but wanted a sanity check to see if that was still the case. For instance, on one quad core low-power system I had, tor would max out at 28% of CPU - using 100% of one core and about 12% of a second (for a total of 112/4 = 28% of the system).
On 5/27/2022 12:55 PM, Roman Mamedov wrote:
On Wed, 25 May 2022 19:31:41 -0500 Thoughts thoughts@kevinsthoughts.com wrote:
For a non-exit relay, is "NumCPUs 2" still the recommended maximum? Running on a quad core and recently saw a message indicating I had insufficient CPU power to support the desired number of connections...
I'm not sure why would it be "the recommended maximum" to begin with.
It would make sense in context of running 2 instances of Tor on a 4-core machine, to limit each to 2 CPUs, and then pin them to cores 0-1 and 2-3 respectively with "taskset", for better cache locality and to ensure they never interfere with each other.
Running only 1 instance with "NumCPUs 4" will not be as effective in total throughput as the setup described above. But if you aren't going to run a 2nd instance in any case, there's nothing to stop you from setting that to 4, or removing that line altogether and letting Tor autodetect the number of cores.