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Merge pull request #3097 from smoe/install_docs_changes
docs: translation-triggered changes on latency-test (smoe:install_docs_changes)
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docs/src/install/latency-test.adoc

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@@ -32,8 +32,6 @@ However, software step pulses also have some disadvantages:
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- loads the CPU
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[[sec:latency-tests]]
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== Latency Tests(((Latency Tests)))
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@@ -55,16 +53,16 @@ and run the following command:
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latency-test
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----
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This will start the latency test with a base-thread period of 25uS and a
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servo-thread period of 1mS. The period times may be specified on the command
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This will start the latency test with a base-thread period of 25 µs and a
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servo-thread period of 1 ms. The period times may be specified on the command
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line:
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----
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latency-test 50000 1000000
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----
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This will start the latency test with a base-thread period of 50uS and a
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servo-thread period of 1mS.
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servo-thread period of 1 ms.
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For available options, on the command line enter:
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@@ -93,18 +91,18 @@ You should run the test for at least several minutes; sometimes
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the worst case latency doesn't happen very often, or only happens
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when you do some particular action. For instance, one Intel
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motherboard worked pretty well most of the time, but every 64
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seconds it had a very bad 300 us latency. Fortunately that was
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fixable, see https://wiki.linuxcnc.org/cgi-bin/wiki.pl?FixingSMIIssues
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seconds it had a very bad 300 µs latency. Fortunately that was
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fixable, see https://wiki.linuxcnc.org/cgi-bin/wiki.pl?FixingSMIIssues .
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So, what do the results mean? If your Max Jitter number is less
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than about 15-20 microseconds (15000-20000 nanoseconds), the
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computer should give very nice results with software stepping. If
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the max latency is more like 30-50 microseconds, you can still
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computer should give very nice results with software stepping.
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If the max latency is more like 30-50 microseconds, you can still
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get good results, but your maximum step rate might be a little
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disappointing, especially if you use microstepping or have very
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fine pitch leadscrews. If the numbers are 100 us or more (100,000
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nanoseconds), then the PC is not a good candidate for software
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stepping. Numbers over 1 millisecond (1,000,000 nanoseconds) mean
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fine pitch leadscrews. If the numbers are 100 µs or more,
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i.e. >= 100,000 nanoseconds (ns), then the PC is not a good candidate for software
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stepping. Numbers over 1 millisecond (1,000,000 ns) mean
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the PC is not a good candidate for LinuxCNC, regardless of whether you
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use software stepping or not.
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For more information on stepper tuning see the
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<<cha:stepper-tuning,Stepper Tuning>> Chapter.
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*Additional command line tools are available for examining latency
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when LinuxCNC is not running.*
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[TIP]
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Additional command line tools are available for examining latency
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when LinuxCNC is not running.
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=== Latency Plot
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latency-plot --hal [Options]
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Options:
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--base nS (base thread interval, default: 25000)
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--servo nS (servo thread interval, default: 1000000)
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--time mS (report interval, default: 1000)
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--base ns (base thread interval in nanoseconds, default: 25000)
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--servo ns (servo thread interval in nanoseconds, default: 1000000)
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--time ms (report interval in milliseconds, default: 1000)
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--relative (relative clock time (default))
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--actual (actual clock time)
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----
@@ -147,7 +146,7 @@ image::../config/images/latency-plot.png["latency-plot Window"]
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=== Latency Histogram
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latency-histogram displays a histogram of latency (jitter) for
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The application latency-histogram displays a histogram of latency (jitter) for
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a base and servo thread.
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latency-histogram [Options]
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Options:
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--base nS (base thread interval, default: 25000, min: 5000)
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--servo nS (servo thread interval, default: 1000000, min: 25000)
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--bbinsize nS (base bin size, default: 100
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--sbinsize nS (servo bin size, default: 100
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--base ns (base thread interval in nanoseconds, default: 25000, min: 5000)
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--servo ns (servo thread interval in nanoseconds, default: 1000000, min: 25000)
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--bbinsize ns (base bin size in nanoseconds, default: 100
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--sbinsize ns (servo bin size in nanoseconds, default: 100
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--bbins n (base bins, default: 200
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--sbins n (servo bins, default: 200
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--logscale 0|1 (y axis log scale, default: 1)
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--nox (no gui, display elapsed,min,max,sdev for each thread)
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Notes:
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Linuxcnc and Hal should not be running, stop with halrun -U.
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Large number of bins and/or small binsizes will slow updates.
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For single thread, specify --nobase (and options for servo thread).
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Measured latencies outside of the +/- bin range are reported
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with special end bars. Use --show to show count for
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the off-chart [pos|neg] bin
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LinuxCNC and HAL should not be running, stop with halrun -U.
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Large number of bins and/or small binsizes will slow updates.
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For single thread, specify --nobase (and options for servo thread).
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Measured latencies outside of the +/- bin range are reported
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with special end bars. Use --show to show count for
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the off-chart [pos|neg] bin
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----
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.`latency-histogram` Window

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