Spdk/overhead at ed1e7ca2d7d51a4d79aeb143ed92bf03b8505e90 - Spdk

History

Ben Walker 02a17e193e env: Replace DPDK atomics with gcc standard calls Use standard GCC style atomic operations instead of the DPDK calls. The DPDK calls end up translating to the gcc standard inline calls in the generic case anyway. Change-Id: I0ea760c4e23c3660b082a803bbc174de7250f365 Signed-off-by: Ben Walker <benjamin.walker@intel.com>		2016-10-12 09:53:32 -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: Replace DPDK atomics with gcc standard calls	2016-10-12 09:53:32 -07:00
README	nvme: add new test application to measure SW overhead	2016-08-01 12:58:30 -07:00

README

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.