lctl set_param should have an option to set a parameter across multiple matched files in parallel. For instance, if you execute this lctl set_param command:
it should write "clear" to the files matching the given parameter pattern in parallel.
This enhancement is required to speed up clearing of Lustre caches. When there are many OSTs, executing
takes a long time, and there is no reason that the lru_size files can't be written to in parallel. Then the work can be done on each OST in parallel.
For example, with 16 OSTs, it takes 5.4 seconds to clear caches across all namespaces. This could be sped up by parallelizing the write to lru_size across the namespaces.
If this enhancement is added, then
LU-3970 can also be resolved.