Spdk/test/lib/nvme/overhead
Ben Walker 0dd80395f3 env: Move pci.c from util to env
This allows users to swap their PCI library from
libpciaccess/dpdk to another mechanism using the standard
method for swapping out the env library.

Change-Id: Ib2248f8b43754a540de2ec01897e571f0302b667
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
2016-10-05 11:53:24 -07:00
..
.gitignore nvme: add gitignore to overhead directory 2016-08-02 14:33:21 -07:00
Makefile env: Make the environment library configurable. 2016-10-05 11:51:37 -07:00
overhead.c env: Move pci.c from util to env 2016-10-05 11:53:24 -07:00
README nvme: add new test application to measure SW overhead 2016-08-01 12:58:30 -07:00

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.