Latency uses parameter block size when stonewalling is enabled

[karthjyojay]

Hi there!

We noticed that the latency value seems to be calculated by the command block size parameter instead of the number of bytes that actually got written/read. We ran a few sample commands here. We ran IOR with -t 1G and block size of 10G, 100G, 1000G, 10000G, and 100000G. Each latency value seemed to decrease inversely by the same factor of 10. The code for latency calculation also seems to use the parameter size and not the size of what was actually read/written.

Should the actual number of bytes be used in latency calculation, or is there a field that does this?

Example Test Runs with minimum output:

[root@client]# cat /tmp/ior-easy-results/ior-easy-write-summary.txt
IOR-3.4.0+dev: MPI Coordinated Test of Parallel I/O
Began               : Sat Jun 29 00:09:43 2024
Command line        : /opt/io500-sc22/bin/ior -e -k -O summaryFile=/tmp/ior-easy-results/ior-easy-write-summary.txt -O saveRankPerformanceDetailsCSV=/tmp/ior-easy-results/ior-easy-write.csv -t 1G -b 10G -s 1 -o /mnt/mnt/ior-easy -a POSIX -w -F --dataPacketType=timestamp -C -Q 1 -g -G 1719619473 -D 60 -O stoneWallingWearOut=1 -O stoneWallingStatusFile=/tmp/ior-easy-results/ior-easy.stonewall

Latency(s)
---------- 
 0.778828

[root@client]# cat /tmp/ior-easy-results/ior-easy-write-summary.txt
IOR-3.4.0+dev: MPI Coordinated Test of Parallel I/O
Began               : Sat Jun 29 00:10:14 2024
Command line        : /opt/io500-sc22/bin/ior -e -k -O summaryFile=/tmp/ior-easy-results/ior-easy-write-summary.txt -O saveRankPerformanceDetailsCSV=/tmp/ior-easy-results/ior-easy-write.csv -t 1G -b 100G -s 1 -o /mnt/mnt/ior-easy -a POSIX -w -F --dataPacketType=timestamp -C -Q 1 -g -G 1719619473 -D 60 -O stoneWallingWearOut=1 -O stoneWallingStatusFile=/tmp/ior-easy-results/ior-easy.stonewall

Latency(s)
 0.603770 

[root@client]# cat /tmp/ior-easy-results/ior-easy-write-summary.txt
IOR-3.4.0+dev: MPI Coordinated Test of Parallel I/O
Began               : Sat Jun 29 00:11:51 2024
Command line        : /opt/io500-sc22/bin/ior -e -k -O summaryFile=/tmp/ior-easy-results/ior-easy-write-summary.txt -O saveRankPerformanceDetailsCSV=/tmp/ior-easy-results/ior-easy-write.csv -t 1G -b 1000G -s 1 -o /mnt/mnt/ior-easy -a POSIX -w -F --dataPacketType=timestamp -C -Q 1 -g -G 1719619473 -D 60 -O stoneWallingWearOut=1 -O stoneWallingStatusFile=/tmp/ior-easy-results/ior-easy.stonewall

Results:
Latency(s) 
0.060289  

[root@client]# cat /tmp/ior-easy-results/ior-easy-write-summary.txt
IOR-3.4.0+dev: MPI Coordinated Test of Parallel I/O
Began               : Sat Jun 29 00:13:25 2024
Command line        : /opt/io500-sc22/bin/ior -e -k -O summaryFile=/tmp/ior-easy-results/ior-easy-write-summary.txt -O saveRankPerformanceDetailsCSV=/tmp/ior-easy-results/ior-easy-write.csv -t 1G -b 10000G -s 1 -o /mnt/mnt/ior-easy -a POSIX -w -F --dataPacketType=timestamp -C -Q 1 -g -G 1719619473 -D 60 -O stoneWallingWearOut=1 -O stoneWallingStatusFile=/tmp/ior-easy-results/ior-easy.stonewall

Results:

 Latency(s)
 0.006072   
 
[root@client]# cat /tmp/ior-easy-results/ior-easy-write-summary.txt
IOR-3.4.0+dev: MPI Coordinated Test of Parallel I/O
Began               : Sat Jun 29 00:14:59 2024
Command line        : /opt/io500-sc22/bin/ior -e -k -O summaryFile=/tmp/ior-easy-results/ior-easy-write-summary.txt -O saveRankPerformanceDetailsCSV=/tmp/ior-easy-results/ior-easy-write.csv -t 1G -b 100000G -s 1 -o /mnt/mnt/ior-easy -a POSIX -w -F --dataPacketType=timestamp -C -Q 1 -g -G 1719619473 -D 60 -O stoneWallingWearOut=1 -O stoneWallingStatusFile=/tmp/ior-easy-results/ior-easy.stonewall

Results:
Latency(s)
0.000607