a sample project to show how to use jmh. Currently, it includes two benchmarks:
- logger performance comparison: compares slf4j with log4j binding and log4j2 performance
To run all the benchmarks:
mvn clean install
java -jar target/benchmarks.jar #default behavior -wi 20 -i 20 -f 10
java -jar target/benchmarks.jar -wi 5 -i 5 -f 1To run individual benchmarks:
mvn clean install
java -cp target/benchmark.jar com.tutorial.jmh.LoggerPerformance #runs logger performance benchmark
java -cp target/benchmark.jar com.tutorial.jmh.Multiplication #runs multiplication benchmarkHere is some sample benchmark results. It shows that log4j2 logger has x50 throughput compared with slf4j with log4j binding. It also shows that using a primitive long value has more than 3000x throughput than using BigInteger when doing multiplication.
# Run complete. Total time: 00:02:50
Benchmark Mode Cnt Score Error Units
LoggerPerformance.testLog4j2 thrpt 5 497266495.488 ± 37639153.467 ops/s
LoggerPerformance.testLog4j2CheckLevel thrpt 5 493116489.550 ± 27628495.284 ops/s
LoggerPerformance.testSlf4j thrpt 5 12103070.008 ± 1392945.915 ops/s
LoggerPerformance.testSlf4jCheckLevel thrpt 5 11807391.240 ± 2244919.154 ops/s
Multiplication.test10 thrpt 5 3152.392 ± 406.268 ops/us
Multiplication.test10BigInteger thrpt 5 1.105 ± 0.054 ops/us
Multiplication.test20 thrpt 5 3202.390 ± 401.265 ops/us
Multiplication.test20BigInteger thrpt 5 0.514 ± 0.029 ops/us
Multiplication.test10 avgt 5 ≈ 10⁻³ us/op
Multiplication.test10BigInteger avgt 5 0.903 ± 0.055 us/op
Multiplication.test20 avgt 5 ≈ 10⁻⁴ us/op
Multiplication.test20BigInteger avgt 5 1.959 ± 0.113 us/op
Multiplication.test10 sample 63727 0.044 ± 0.002 us/op
Multiplication.test10BigInteger sample 86209 0.953 ± 0.055 us/op
Multiplication.test20 sample 64363 0.042 ± 0.001 us/op
Multiplication.test20BigInteger sample 79731 1.992 ± 0.036 us/op
Multiplication.test10 ss 5 1.434 ± 0.919 us/op
Multiplication.test10BigInteger ss 5 71.377 ± 51.099 us/op
Multiplication.test20 ss 5 1.404 ± 1.085 us/op
Multiplication.test20BigInteger ss 5 176.121 ± 100.931 us/op$ java -jar target/benchmarks.jar -h
Usage: java -jar ... [regexp*] [options]
[opt] means optional argument.
<opt> means required argument.
"+" means comma-separated list of values.
"time" arguments accept time suffixes, like "100ms".
[arguments] Benchmarks to run (regexp+).
-bm <mode> Benchmark mode. Available modes are: [Throughput/thrpt,
AverageTime/avgt, SampleTime/sample, SingleShotTime/ss,
All/all]
-bs <int> Batch size: number of benchmark method calls per
operation. Some benchmark modes may ignore this
setting, please check this separately.
-e <regexp+> Benchmarks to exclude from the run.
-f <int> How many times to fork a single benchmark. Use 0 to
disable forking altogether. Warning: disabling
forking may have detrimental impact on benchmark
and infrastructure reliability, you might want
to use different warmup mode instead.
-foe <bool> Should JMH fail immediately if any benchmark had
experienced an unrecoverable error? This helps
to make quick sanity tests for benchmark suites,
as well as make the automated runs with checking error
codes.
-gc <bool> Should JMH force GC between iterations? Forcing
the GC may help to lower the noise in GC-heavy benchmarks,
at the expense of jeopardizing GC ergonomics decisions.
Use with care.
-h Display help.
-i <int> Number of measurement iterations to do. Measurement
iterations are counted towards the benchmark score.
-jvm <string> Use given JVM for runs. This option only affects forked
runs.
-jvmArgs <string> Use given JVM arguments. Most options are inherited
from the host VM options, but in some cases you want
to pass the options only to a forked VM. Either single
space-separated option line, or multiple options
are accepted. This option only affects forked runs.
-jvmArgsAppend <string> Same as jvmArgs, but append these options before
the already given JVM args.
-jvmArgsPrepend <string> Same as jvmArgs, but prepend these options before
the already given JVM arg.
-l List the benchmarks that match a filter, and exit.
-lp List the benchmarks that match a filter, along with
parameters, and exit.
-lprof List profilers.
-lrf List machine-readable result formats.
-o <filename> Redirect human-readable output to a given file.
-opi <int> Override operations per invocation, see @OperationsPerInvocation
Javadoc for details.
-p <param={v,}*> Benchmark parameters. This option is expected to
be used once per parameter. Parameter name and parameter
values should be separated with equals sign. Parameter
values should be separated with commas.
-prof <profiler> Use profilers to collect additional benchmark data.
Some profilers are not available on all JVMs and/or
all OSes. Please see the list of available profilers
with -lprof.
-r <time> Minimum time to spend at each measurement iteration.
Benchmarks may generally run longer than iteration
duration.
-rf <type> Format type for machine-readable results. These
results are written to a separate file (see -rff).
See the list of available result formats with -lrf.
-rff <filename> Write machine-readable results to a given file.
The file format is controlled by -rf option. Please
see the list of result formats for available formats.
-si <bool> Should JMH synchronize iterations? This would significantly
lower the noise in multithreaded tests, by making
sure the measured part happens only when all workers
are running.
-t <int> Number of worker threads to run with. 'max' means
the maximum number of hardware threads available
on the machine, figured out by JMH itself.
-tg <int+> Override thread group distribution for asymmetric
benchmarks. This option expects a comma-separated
list of thread counts within the group. See @Group/@GroupThreads
Javadoc for more information.
-to <time> Timeout for benchmark iteration. After reaching
this timeout, JMH will try to interrupt the running
tasks. Non-cooperating benchmarks may ignore this
timeout.
-tu <TU> Override time unit in benchmark results. Available
time units are: [m, s, ms, us, ns].
-v <mode> Verbosity mode. Available modes are: [SILENT, NORMAL,
EXTRA]
-w <time> Minimum time to spend at each warmup iteration. Benchmarks
may generally run longer than iteration duration.
-wbs <int> Warmup batch size: number of benchmark method calls
per operation. Some benchmark modes may ignore this
setting.
-wf <int> How many warmup forks to make for a single benchmark.
All iterations within the warmup fork are not counted
towards the benchmark score. Use 0 to disable warmup
forks.
-wi <int> Number of warmup iterations to do. Warmup iterations
are not counted towards the benchmark score.
-wm <mode> Warmup mode for warming up selected benchmarks.
Warmup modes are: INDI = Warmup each benchmark individually,
then measure it. BULK = Warmup all benchmarks first,
then do all the measurements. BULK_INDI = Warmup
all benchmarks first, then re-warmup each benchmark
individually, then measure it.
-wmb <regexp+> Warmup benchmarks to include in the run in addition
to already selected by the primary filters. Harness
will not measure these benchmarks, but only use them
for the warmup.