"sqlio -L" - Latencies from System/Processor Timer

Q

What is the Latencies from System/Processor Timer option, "sqlio -L"?

✍: FYIcenter.com

A

The Latencies from System/Processor Timer option, "sqlio -L", flags the test to include Latency measurements using the system timer or the process timer.

Example 1 - Run SQLIO to include Latency measurements using the system timer:

C:\fyicenter\SQLIO>sqlio -LS

using system counter for latency timings, 2343896 counts per second
1 thread reading for 30 secs from file testfile.dat
        using 2KB IOs over 128KB stripes with 64 IOs per run
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec: 12522.98
MBs/sec:    24.45
latency metrics:
Min_Latency(ms): 0
Avg_Latency(ms): 0
Max_Latency(ms): 36
histogram:
ms: 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24+
%: 100  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0

Example 2 - Run SQLIO to include Latency measurements using the process timer:

C:\fyicenter\SQLIO>sqlio -LP

calibrating timestamp counter for latency timings... done (MHz measured at 2371)

1 thread reading for 30 secs from file testfile.dat
        using 2KB IOs over 128KB stripes with 64 IOs per run
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec: 12508.75
MBs/sec:    24.43
latency metrics:
Min_Latency(ms): 0
Avg_Latency(ms): 0
Max_Latency(ms): 9
histogram:
ms: 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24+
%: 100  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0

It looks like reading a block of 2KB takes less than 1 ms most of the time.

 

"sqlio -s" - Number of Seconds to Run

SQLIO Related Terminology

Getting Started with Microsoft SQLIO

⇑⇑ SQLIO Disk I/O Benchmark Test Tutorials

2019-08-19, 173👍, 0💬