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This question already has an answer here:

How can I benchmark individual cores? I want to see if they are all operating at the same speed. I'm a bit confused if my Cortex A53 device has big.LITTLE or not, I'm reading conflicting information on the internet, so I want to test it myself.

marked as duplicate by Panther, Charles Green, user364819, Eric Carvalho, WinEunuuchs2Unix Jul 16 '17 at 21:40

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  • It's definitely not a duplicate, I'm asking about individual cores. There's no mention of that on that link – ycomp Jul 14 '17 at 16:27
  • I use taskset to limit execution to one CPU or two CPUs on the same core, and then whatever stress or benchmark program you want. – Doug Smythies Jul 14 '17 at 21:49
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(I am assuming you have a cpu with multiple cores which each has multiple threads)

You can use a tool named sysbench.

Install it with sudo apt-get install sysbench

By default this is testing a single thread.

sysbench --test=cpu run

or

sysbench --test=threads --num-threads=1 --thread-locks=1 run

But I can not seem to figure out how to lock it to a specific thread. Someone?

You can try it yourself by reading the man pages:

man sysbench
  • It's not hyperthreaded – ycomp Jul 14 '17 at 17:28
  • Ok. But still this leaves the question: how to lock it to one core. Alternatively you could disable all the other cores in the bios. And check during sysbench the system monitor gui to be sure. – urben Jul 14 '17 at 19:41
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I think this comment by @doug-smythies answers the question.

However, I realized just to see if all CPUs were performing at the same level - I could do this:

1 CPU

root@amlogic:~# stress-ng --cpu 1 --cpu-method matrixprod  --metrics-brief --perf -t 10
stress-ng: info:  [5921] dispatching hogs: 1 cpu
stress-ng: info:  [5921] cache allocate: using built-in defaults as unable to determine cache details
stress-ng: info:  [5921] cache allocate: default cache size: 2048K
stress-ng: info:  [5921] successful run completed in 10.94s
stress-ng: info:  [5921] stressor      bogo ops real time  usr time  sys time   bogo ops/s   bogo ops/s
stress-ng: info:  [5921]                          (secs)    (secs)    (secs)   (real time) (usr+sys time)
stress-ng: info:  [5921] cpu                 21     10.93     10.02      0.02         1.92         2.09
stress-ng: info:  [5921] cpu:
stress-ng: info:  [5921]             14,108,856,703 CPU Cycles                     1.29 B/sec
stress-ng: info:  [5921]             13,710,373,770 Instructions                   1.25 B/sec (0.972 instr. per cycle)
stress-ng: info:  [5921]                927,478,656 Cache References              84.76 M/sec
stress-ng: info:  [5921]                 43,400,148 Cache Misses                   3.97 M/sec ( 4.68%)
stress-ng: info:  [5921]                 36,225,340 Branch Misses                  3.31 M/sec ( 0.00%)

4 CPU

root@amlogic:~# stress-ng --cpu 4 --cpu-method matrixprod  --metrics-brief --perf -t 10
stress-ng: info:  [5867] dispatching hogs: 4 cpu
stress-ng: info:  [5867] cache allocate: using built-in defaults as unable to determine cache details
stress-ng: info:  [5867] cache allocate: default cache size: 2048K
stress-ng: info:  [5867] successful run completed in 11.56s
stress-ng: info:  [5867] stressor      bogo ops real time  usr time  sys time   bogo ops/s   bogo ops/s
stress-ng: info:  [5867]                          (secs)    (secs)    (secs)   (real time) (usr+sys time)
stress-ng: info:  [5867] cpu                 51     10.80     41.05      0.47         4.72         1.23
stress-ng: info:  [5867] cpu:
stress-ng: info:  [5867]             59,953,532,588 CPU Cycles                     5.19 B/sec
stress-ng: info:  [5867]             31,357,210,848 Instructions                   2.71 B/sec (0.523 instr. per cycle)
stress-ng: info:  [5867]              2,127,678,244 Cache References               0.18 B/sec
stress-ng: info:  [5867]                101,073,952 Cache Misses                   8.75 M/sec ( 4.75%)
stress-ng: info:  [5867]                 82,805,524 Branch Misses                  7.17 M/sec ( 0.00%)

8 CPU

root@amlogic:~# stress-ng --cpu 8 --cpu-method matrixprod  --metrics-brief --perf -t 10
stress-ng: info:  [5892] dispatching hogs: 8 cpu
stress-ng: info:  [5892] cache allocate: using built-in defaults as unable to determine cache details
stress-ng: info:  [5892] cache allocate: default cache size: 2048K
stress-ng: info:  [5892] successful run completed in 11.53s
stress-ng: info:  [5892] stressor      bogo ops real time  usr time  sys time   bogo ops/s   bogo ops/s
stress-ng: info:  [5892]                          (secs)    (secs)    (secs)   (real time) (usr+sys time)
stress-ng: info:  [5892] cpu                126     10.50     81.49      0.58        12.00         1.54
stress-ng: info:  [5892] cpu:
stress-ng: info:  [5892]            118,145,351,216 CPU Cycles                    10.24 B/sec
stress-ng: info:  [5892]             94,066,812,704 Instructions                   8.16 B/sec (0.796 instr. per cycle)
stress-ng: info:  [5892]              6,383,299,240 Cache References               0.55 B/sec
stress-ng: info:  [5892]                304,757,784 Cache Misses                  26.43 M/sec ( 4.77%)
stress-ng: info:  [5892]                248,569,352 Branch Misses                 21.55 M/sec ( 0.00%)
  • I am glad you figured it out. But can you explain how you see that all cpu's are performing the same? Just by plain simply looking at how long the usr time for 1cpu vs 4cpu vs 8 cpu (resp. ~10s vs ~ 40s vs ~80s) took? – urben Jul 17 '17 at 23:59
  • Is it faulty logic? I assumed if the cycles are multiples of the cycles of 1 core. The 4 and 8 results have about 4 and 8 times the cycles, that it couldn't possibly be a big . little configuration, since little cores should be at a lower frequency? – ycomp Jul 18 '17 at 2:21

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