c9c7c281f8
Part of #2256 * achieve * additionally * against * aliases * already * another * arguments * between * capabilities * comparison * compatibility * configuration * continuing * controlq * cpumask * default * depends * dereferenced * discussed * dissect * driver * environment * everything * excluded * existing * expectation * failed * fails * following * functions * hugepages * identifiers * implicitly * in_capsule * increment * initialization * initiator * integrity * iteration * latencies * libraries * management * namespace * negotiated * negotiation * nonexistent * number * occur * occurred * occurring * offsetting * operations * outstanding * overwhelmed * parameter * parameters * partition * preempts * provisioned * responded * segment * skipped * struct * subsystem * success * successfully * sufficiently * this * threshold * transfer * transferred * unchanged * unexpected * unregistered * useless * utility * value * variable * workload Change-Id: I21ca7dab4ef575b5767e50aaeabc34314ab13396 Signed-off-by: Josh Soref <jsoref@gmail.com> Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/10409 Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com> Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com> Reviewed-by: Jim Harris <james.r.harris@intel.com> Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
This application measures the software overhead of I/O submission and completion for both the SPDK NVMe driver and an AIO file handle. It runs a random read, queue depth = 1 workload to a single device, and captures TSC as follows: * Submission: capture TSC before and after the I/O submission call (SPDK or AIO). * Completion: capture TSC before and after the I/O completion check. Only record the TSC delta if the I/O completion check resulted in a completed I/O. Also use heuristics in the AIO case to account for time spent in interrupt handling outside of the actual I/O completion check. Usage: To test software overhead for a 4KB I/O over a 10 second period: SPDK: overhead -s 4096 -t 10 AIO: overhead -s 4096 -t 10 /dev/nvme0n1 Note that for the SPDK case, it will only use the first namespace on the first controller found by SPDK. If a different namespace is desired, attach controllers individually to the kernel NVMe driver to ensure they will not be enumerated by SPDK.