Memstore performance improvements v0.90 vs v0.87

["Blinick, Stephen L" <stephen.l.blinick@intel.com>]

In the process of moving to a new cluster (RHEL7 based) I grabbed v0.90, compiled RPM's and re-ran the simple local-node memstore test I've run on .80 - .87.  It's a single Memstore OSD and a single Rados Bench client locally on the same node.  Increasing queue depth and measuring latency /IOPS.  So far, the measurements have been consistent across different hardware and code releases (with about a 30% improvement with the OpWQ Sharding changes that came in after Firefly). 

These are just very early results, but I'm seeing a very large improvement in latency and throughput with v90 on RHEL7.   Next  I'm working to get lttng installed and working in RHEL7 to determine where the improvement is.   On previous levels, these measurements have been roughly the same using a real (fast) backend (i.e. NVMe flash), and I will verify here as well.   Just wondering if anyone else has measured similar improvements?


100% Reads or Writes, 4K Objects, Rados Bench

========================
V0.87: Ubuntu 14.04LTS

*Writes*
#Thr	IOPS	Latency(ms)
1	618.80		1.61
2	1401.70		1.42
4	3962.73		1.00
8	7354.37		1.10
16	7654.67		2.10
32	7320.33		4.37
64	7424.27		8.62

*Reads*
#thr	IOPS	Latency(ms)
1	837.57		1.19
2	1950.00		1.02
4	6494.03		0.61
8	7243.53		1.10
16	7473.73		2.14
32	7682.80		4.16
64	7727.10		8.28


========================
V0.90:  RHEL7

*Writes*
#Thr	IOPS	Latency(ms)
1	2558.53		0.39
2	6014.67		0.33
4	10061.33	0.40
8	14169.60	0.56
16	14355.63	1.11
32	14150.30	2.26
64	15283.33	4.19

*Reads*
#Thr	IOPS	Latency(ms)
1	4535.63		0.22
2	9969.73		0.20
4	17049.43	0.23
8	19909.70	0.40
16	20320.80	0.79
32	19827.93	1.61
64	22371.17	2.86