samba performance difference between old and the latest ?

[Namjae Jeon]

Hello,

I found something strange during measuring performance with samba these days.
I checked the performance of samba 4.7.6 and 4.10.6. 
There seems to be about 20% performance difference between the two versions.

Test environment
 1. use iozone and dd utils
 2. share is tmpfs
 3. smb client is kernel cifs client
 4. oplock disable, oplock = no
 4. command : ./iozone -s1g -r4 -e -i 0 -t 1 -b 24m.xls -+u

with samba 4.7.6
	Children see throughput for  1 initial writers 	=   11248.48 kB/sec
	Parent sees throughput for  1 initial writers 	=   11248.28 kB/sec
	Min throughput per process 			=   11248.48 kB/sec 
	Max throughput per process 			=   11248.48 kB/sec
	Avg throughput per process 			=   11248.48 kB/sec
	Min xfer 					= 1048576.00 kB
	CPU Utilization: Wall time   93.219    CPU time   29.517    CPU
utilization  

with samba 4.10.6 
Children see throughput for  1 initial writers 	=    9018.82 kB/sec
	Parent sees throughput for  1 initial writers 	=    9018.70 kB/sec
	Min throughput per process 			=    9018.82 kB/sec 
	Max throughput per process 			=    9018.82 kB/sec
	Avg throughput per process 			=    9018.82 kB/sec
	Min xfer 					= 1048576.00 kB
	CPU Utilization: Wall time  116.265    CPU time   33.182    CPU
utilization  


================================================================================
========
dd test result is same with iozone result. 

samba 4.7.6 : 11.6MB/s
samba 4.10.6 : 9.5MB/s

with samba 4.7.6 :
root at test1234-Samsung-DeskTop-System:/mnt/read# dd if=/dev/zero of=1.txt bs=4096
count=1024
1024+0 records in
1024+0 records out
4194304 bytes (4.2 MB, 4.0 MiB) copied, 0.360991 s, 11.6 MB/s

with samba 4.10.6 :
root at test1234-Samsung-DeskTop-System:/mnt/read# dd if=/dev/zero of=1.txt bs=4096
count=1024
1024+0 records in
1024+0 records out
4194304 bytes (4.2 MB, 4.0 MiB) copied, 0.442567 s, 9.5 MB/s

Am I missing something? or real issue ?

Thanks!