Commit 36f9d416 authored by Ziye Yang's avatar Ziye Yang Committed by Daniel Verkamp
Browse files

fio_plugin: update the README 



Describe the phenoemon for peformance difference
between fio + spdk plugin and spdk nvme perf
on multiple NVMe SSDs while both using single
cpu core.

Change-Id: I80c2cfd51cd1d8ec28a11a1a8653469cfc3335eb
Signed-off-by: default avatarZiye Yang <optimistyzy@gmail.com>
Reviewed-on: https://review.gerrithub.io/379573


Tested-by: default avatarSPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: default avatarPaul Luse <paul.e.luse@intel.com>
Reviewed-by: default avatarGangCao <gang.cao@intel.com>
Reviewed-by: default avatarDaniel Verkamp <daniel.verkamp@intel.com>
parent 526d759a

examples/nvme/fio_plugin/README.md

+8 −0
Original line number Diff line number Diff line
@@ -70,3 +70,11 @@ engine's full path via the ioengine parameter - LD_PRELOAD is recommended to avo 
When testing random workloads, it is recommended to set norandommap=1.  fio's random map

processing consumes extra CPU cycles which will degrade performance over time with

the fio_plugin since all I/O are submitted and completed on a single CPU core.



When testing FIO on multiple NVMe SSDs with SPDK plugin, it is recommended to use multiple jobs in FIO configurion.

It has been observed that there are some performance gap between FIO(with SPDK plugin enabled) and SPDK perf

(examples/nvme/perf/perf) on testing multiple NVMe SSDs. If you use one job(i.e., use one CPU core) configured for

FIO test, the performance is worse than SPDK perf (also using one CPU core) against many NVMe SSDs. But if you use

multiple jobs for FIO test, the performance of FIO is similiar with SPDK perf. After analyzing this phenomenon, we

think that is caused by the FIO architecture. Mainly FIO can scale with multiple threads (i.e., using CPU cores),

but it is not good to use one thread against many I/O devices.