A command-line tool to restrict a process from using particular hardware
resources. It is particularly geared towards performance-sensitive
multi-core experiments, in which you may want to avoid or measure the
impact of CPU features like SMT (e.g., Intel Hyper-Threading or
NUMA memory. While this is possible with existing tools like
hwloc-bind and numactl, it's often pretty inconvenient to get
the result you want. With curb on the other hand:
$ curb --no-smt --no-numa mycommand
Will run mycommand only on each physical core on a single NUMA node
(the first one specifically). Note that if you want to pass additional
arguments to the command under test, you can do so using --:
$ curb --no-smt mycommand -- --no-crash --performance better
To visualize what CPUs are being used using lstopo, do:
$ curb --no-smt --no-numa lstopo -- --pid 0
That should show all active cores in green. If you don't have a window
manager running, add -v at the end and look for PUs marked with
(running).
Dependencies
Curb depends on the hwloc crate, which in turn depends on the
hwloc C library.
OS Support
Curb currently only works on cfg(unix) systems, because it sets the
CPU binding for the current process, and then calls exec. This
should be possible to work around by instead spawning the process,
getting its identifier, calling set_cpubind_for_process, and then
waiting for the process to exit. However, this has a number of
downsides, like the process initially being unconstrained and having
to proxy things like stdin, stdout, signals, and exit codes. Suggestions
for how to support non-UNIX platforms are warmly welcome!