samba performance difference between old and the latest ?

[Jeremy Allison]

On Fri, Sep 06, 2019 at 11:01:51AM +0900, Namjae Jeon via samba-technical wrote:
> 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 ?

Is this on identical kernel versions ?