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Version
- GraalVM for JDK 23 (Latest)
- GraalVM for JDK 24 (Early Access)
- GraalVM for JDK 21
- GraalVM for JDK 17
- Archives
- Dev Build
- Ruby Reference
- Compatibility
- Debugging Ruby
- Runtime Configurations
- Using Ruby with GraalVM
- Installing `libssl`
- Installing LibYAML
- Installing Make and GCC
- Installing `zlib`
- Migration from JRuby to Ruby
- TruffleRuby Options and Command Line
- Polyglot Programming
- Ruby Managers and Installers
- Standalone Distribution
- Development Tools for Ruby
- Ruby Additional Functionality
- Setting up a UTF-8 Locale
- Reporting Performance Problems
- Security
- Optcarrot Example
- FAQ
Development Tools for Ruby
TruffleRuby ships with tools automatically provided by GraalVM. Run --help:tools to see a full list of options.
The following program is used for illustration:
require 'chunky_png'
a = ChunkyPNG::Image.from_file('a.png')
b = ChunkyPNG::Image.from_file('b.png')
c = a.compose(b, 0, 0)
c.save('c.png')
VisualVM #
Install VisualVM from its website.
VisualVM is a GUI with many tools:
- monitoring such as CPU usage, heap size, time spent in GC, etc (tab: Monitor)
- capturing and exploring heap dumps (tab: Monitor)
- a list of threads and their status, and thread dumps (tab: Threads)
- CPU and memory sampling profilers at the Java level (tab: Sampler)
- a CPU sampling profiler at the Ruby level (tab: Polyglot Sampler)
There is more documentation about VisualVM on the GraalVM website.
Profiling #
CPU Tracer #
The CPU tracer records the number of times methods, blocks, or statements that are run, and prints a histogram.
Enable it with --cputracer:
-----------------------------------------------------------------------------------------------------------------------------------
Tracing Histogram. Counted a total of 41663 element executions.
Total Count: Number of times the element was executed and percentage of total executions.
Interpreted Count: Number of times the element was interpreted and percentage of total executions of this element.
Compiled Count: Number of times the compiled element was executed and percentage of total executions of this element.
-----------------------------------------------------------------------------------------------------------------------------------
Name | Total Count | Interpreted Count | Compiled Count | Location
-----------------------------------------------------------------------------------------------------------------------------------
ChunkyPNG::Color#a | 6474 15.5% | 6474 100.0% | 0 0.0% | chunky_png/color.rb~296-298:12189-12237
block in ChunkyPNG::Canvas::PNGDecoding#decode_png_str_scanline_paeth | 5248 12.6% | 5248 100.0% | 0 0.0% | chunky_png/canvas/png_decoding.rb~476:25098-25131
ChunkyPNG::Color#int8_mult | 3619 8.7% | 3619 100.0% | 0 0.0% | chunky_png/color.rb~344-347:13821-13900
ChunkyPNG::Canvas#width | 3205 7.7% | 3205 100.0% | 0 0.0% | chunky_png/canvas.rb~50:1853-1874
block in ChunkyPNG::Canvas::PNGEncoding#encode_png_str_scanline_up | 3072 7.4% | 3072 100.0% | 0 0.0% | chunky_png/canvas/png_encoding.rb~404:20111-20145
ChunkyPNG::Canvas#get_pixel | 2048 4.9% | 2048 100.0% | 0 0.0% | chunky_png/canvas.rb~184-186:7144-7203
ChunkyPNG::Color#opaque? | 1872 4.5% | 1872 100.0% | 0 0.0% | chunky_png/color.rb~304-306:12410-12468
ChunkyPNG::Color#fully_transparent? | 1500 3.6% | 1500 100.0% | 0 0.0% | chunky_png/color.rb~327-329:13138-13207
block in ChunkyPNG::Canvas::PNGDecoding#decode_png_str_scanline_up | 1408 3.4% | 1408 100.0% | 0 0.0% | chunky_png/canvas/png_decoding.rb~453:24009-24042
block in ChunkyPNG::Canvas::PNGDecoding#decode_png_str_scanline_sub | 1280 3.1% | 1280 100.0% | 0 0.0% | chunky_png/canvas/png_decoding.rb~443:23517-23550
ChunkyPNG::Color#b | 1037 2.5% | 1037 100.0% | 0 0.0% | chunky_png/color.rb~288-290:11969-12024
ChunkyPNG::Color#r | 1036 2.5% | 1036 100.0% | 0 0.0% | chunky_png/color.rb~272-274:11534-11590
ChunkyPNG::Color#g | 1035 2.5% | 1035 100.0% | 0 0.0% | chunky_png/color.rb~280-282:11752-11808
ChunkyPNG::Color#compose_quick | 1024 2.5% | 1024 100.0% | 0 0.0% | chunky_png/color.rb~358-368:14300-14740
ChunkyPNG::Canvas#set_pixel | 1024 2.5% | 1024 100.0% | 0 0.0% | chunky_png/canvas.rb~149-151:5706-5780
block (2 levels) in ChunkyPNG::Canvas::Operations#compose! | 1024 2.5% | 1024 100.0% | 0 0.0% | chunky_png/canvas/operations.rb~58:2331-2367
block in ChunkyPNG::Palette#opaque? | 848 2.0% | 848 100.0% | 0 0.0% | chunky_png/palette.rb~89:3319-3361
SortedSet#add | 848 2.0% | 848 100.0% | 0 0.0% | lib/mri/set.rb~741-745:1000-1169
ChunkyPNG::Color#rgba | 518 1.2% | 518 100.0% | 0 0.0% | chunky_png/color.rb~100-102:3905-3973
block in ChunkyPNG::Canvas::PNGDecoding#decode_png_str_scanline_average | 256 0.6% | 256 100.0% | 0 0.0% | chunky_png/canvas/png_decoding.rb~464:24513-24546
rb_str_new | 199 0.5% | 199 100.0% | 0 0.0% | src/main/c/cext/ruby.c~837:23634-23684
is_managed_rstring_ptr | 193 0.5% | 193 100.0% | 0 0.0% | src/main/c/cext/ruby.c~832:23499-23538
is_rstring_ptr | 193 0.5% | 193 100.0% | 0 0.0% | src/main/c/cext/ruby.c~828:23430-23461
strlen | 190 0.5% | 190 100.0% | 0 0.0% | string.c~56:0
rb_str_new_cstr | 190 0.5% | 190 100.0% | 0 0.0% | src/main/c/cext/ruby.c~858:24268-24310
RB_NIL_P | 138 0.3% | 138 100.0% | 0 0.0% | src/main/c/cext/ruby.c~413:11068-11094
Note how the C function strlen and the C preprocessor macro RB_NIL_P show up, being called by the zlib C extension.
CPU Sampler #
The CPU tracer records the cumulative time spent executing methods, blocks, or statements, and prints a histogram. Enable it with --cpusampler:
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sampling Histogram. Recorded 3895 samples with period 1ms.
Self Time: Time spent on the top of the stack.
Total Time: Time spent somewhere on the stack.
Opt %: Percent of time spent in compiled and therefore non-interpreted code.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Thread: Thread[main,5,main]
Name | Total Time | Opt % || Self Time | Opt % | Location
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------
<main> | 3635ms 93.3% | 0.0% || 1086ms 27.9% | 0.0% | test.rb~1-6:0-140
<top (required)> | 1068ms 27.4% | 0.0% || 708ms 18.2% | 0.0% | chunky_png.rb~1-179:0-5528
block in ChunkyPNG::Canvas::PNGEncoding#encode_png_str_scanline_up | 643ms 16.5% | 0.0% || 643ms 16.5% | 0.0% | chunky_png/canvas/png_encoding.rb~404:20111-20145
__sulong_dispose_context | 260ms 6.7% | 0.0% || 257ms 6.6% | 0.0% | sulong_dispose_context.c~33:0
block in ChunkyPNG::Canvas::PNGDecoding#decode_png_str_scanline_paeth | 58ms 1.5% | 0.0% || 58ms 1.5% | 0.0% | chunky_png/canvas/png_decoding.rb~476:25098-25131
do_checksum | 77ms 2.0% | 0.0% || 47ms 1.2% | 0.0% | src/main/c/zlib/zlib.c~389:12721-12796
ChunkyPNG::Palette#initialize | 52ms 1.3% | 0.0% || 41ms 1.1% | 0.0% | chunky_png/palette.rb~21-24:954-1074
block in Gem::Specification.load | 39ms 1.0% | 0.0% || 39ms 1.0% | 0.0% | bigdecimal-1.4.1.gemspec~5:126-154
rb_define_method | 50ms 1.3% | 0.0% || 36ms 0.9% | 0.0% | src/main/c/cext/ruby.c~2185:61849-61941
rb_tr_init | 44ms 1.1% | 0.0% || 34ms 0.9% | 0.0% | src/main/c/cext/ruby.c~93:2351-2384
<top (required)> | 42ms 1.1% | 0.0% || 33ms 0.8% | 0.0% | chunky_png/canvas.rb~1-372:0-13593
__sulong_byte_array_to_native | 30ms 0.8% | 0.0% || 30ms 0.8% | 0.0% | crt0.c~59:0
rb_str_new | 33ms 0.8% | 0.0% || 29ms 0.7% | 0.0% | src/main/c/cext/ruby.c~837:23634-23684
__sulong_init_context | 68ms 1.7% | 0.0% || 26ms 0.7% | 0.0% | crt0.c~80:0
Init_zlib | 145ms 3.7% | 0.0% || 24ms 0.6% | 0.0% | src/main/c/zlib/zlib.c~4465:112360-112374
rb_zlib_crc32 | 101ms 2.6% | 0.0% || 24ms 0.6% | 0.0% | src/main/c/zlib/zlib.c~473:14760-14808
rb_data_typed_object_wrap | 21ms 0.5% | 0.0% || 21ms 0.5% | 0.0% | src/main/c/cext/ruby.c~2834:79544-79639
rb_tr_load_library | 22ms 0.6% | 0.0% || 20ms 0.5% | 0.0% | src/main/c/cext/ruby.c~2906:81858-81897
ChunkyPNG::Canvas::PNGEncoding#encode_png_str_scanline_up | 662ms 17.0% | 0.0% || 19ms 0.5% | 0.0% | chunky_png/canvas/png_encoding.rb~403-409:20027-20347
rb_define_class_id_under | 18ms 0.5% | 0.0% || 18ms 0.5% | 0.0% | src/main/c/cext/ruby.c~2165:61106-61178
ChunkyPNG::Chunk.read | 137ms 3.5% | 0.0% || 17ms 0.4% | 0.0% | chunky_png/chunk.rb~18-26:783-1054
Datastream | 15ms 0.4% | 0.0% || 15ms 0.4% | 0.0% | chunky_png/datastream.rb~11:364-381
ChunkyPNG::Color#compose_quick | 37ms 0.9% | 0.0% || 14ms 0.4% | 0.0% | chunky_png/color.rb~358-368:14300-14740
rb_deflate_s_deflate | 27ms 0.7% | 0.0% || 13ms 0.3% | 0.0% | src/main/c/zlib/zlib.c~1622:44042-44097
ChunkyPNG::Canvas::PNGDecoding#decode_png_str_scanline_paeth | 71ms 1.8% | 0.0% || 13ms 0.3% | 0.0% | chunky_png/canvas/png_decoding.rb~475-488:25010-25650
ChunkyPNG::Palette.from_canvas | 64ms 1.6% | 0.0% || 12ms 0.3% | 0.0% | chunky_png/palette.rb~63-68:2377-2629
__sulong_byte_arrays_to_native | 42ms 1.1% | 0.0% || 12ms 0.3% | 0.0% | crt0.c~69:0
ChunkyPNG::Chunk::ImageData.combine_chunks | 167ms 4.3% | 0.0% || 12ms 0.3% | 0.0% | chunky_png/chunk.rb~247-253:9766-9980
rb_inflate_initialize | 19ms 0.5% | 0.0% || 12ms 0.3% | 0.0% | src/main/c/zlib/zlib.c~1887:51522-51576
strlen | 12ms 0.3% | 0.0% || 12ms 0.3% | 0.0% | string.c~56:0
zstream_run | 76ms 2.0% | 0.0% || 12ms 0.3% | 0.0% | src/main/c/zlib/zlib.c~1024:27867-27929
By default you see this histogram, but you can also see a call tree with --cpusampler.Output=calltree.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sampling CallTree. Recorded 3102 samples with period 1ms.
Self Time: Time spent on the top of the stack.
Total Time: Time spent somewhere on the stack.
Opt %: Percent of time spent in compiled and therefore non-interpreted code.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Thread: Thread[main,5,main]
Name | Total Time | Opt % || Self Time | Opt % | Location
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
ChunkyPNG::Canvas::PNGEncoding#save | 582ms 18.8% | 0.0% || 5ms 0.2% | 0.0% | chunky_png/canvas/png_encoding.rb~42-44:1754-1871
block in ChunkyPNG::Canvas::PNGEncoding#save | 577ms 18.6% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/canvas/png_encoding.rb~43:1797-1861
ChunkyPNG::Canvas::PNGEncoding#write | 577ms 18.6% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/canvas/png_encoding.rb~34-36:1430-1521
ChunkyPNG::Image#to_datastream | 571ms 18.4% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/image.rb~61-65:2314-2447
ChunkyPNG::Canvas::PNGEncoding#to_datastream | 569ms 18.3% | 0.0% || 1ms 0.0% | 0.0% | chunky_png/canvas/png_encoding.rb~74-89:3715-4561
ChunkyPNG::Canvas::PNGEncoding#encode_png_pixelstream | 489ms 15.8% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/canvas/png_encoding.rb~153-165:7702-8570
ChunkyPNG::Canvas::PNGEncoding#encode_png_image_without_interlacing | 489ms 15.8% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/canvas/png_encoding.rb~172-176:8925-9195
ChunkyPNG::Canvas::PNGEncoding#encode_png_image_pass_to_stream | 489ms 15.8% | 0.0% || 3ms 0.1% | 0.0% | chunky_png/canvas/png_encoding.rb~203-231:10502-11685
block in ChunkyPNG::Canvas::PNGEncoding#encode_png_image_pass_to_stream | 481ms 15.5% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/canvas/png_encoding.rb~225:11418-11456
ChunkyPNG::Canvas::PNGEncoding#encode_png_str_scanline_up | 481ms 15.5% | 0.0% || 11ms 0.4% | 0.0% | chunky_png/canvas/png_encoding.rb~403-409:20027-20347
block in ChunkyPNG::Canvas::PNGEncoding#encode_png_str_scanline_up | 470ms 15.2% | 0.0% || 470ms 15.2% | 0.0% | chunky_png/canvas/png_encoding.rb~404:20111-20145
block in ChunkyPNG::Canvas::PNGEncoding#encode_png_image_pass_to_stream | 5ms 0.2% | 0.0% || 1ms 0.0% | 0.0% | chunky_png/canvas/png_encoding.rb~219:11252-11284
ChunkyPNG::Canvas::PNGEncoding#encode_png_pixels_to_scanline_truecolor_8bit | 4ms 0.1% | 0.0% || 4ms 0.1% | 0.0% | chunky_png/canvas/png_encoding.rb~236-238:11896-12009
ChunkyPNG::Canvas::PNGEncoding#determine_png_encoding | 60ms 1.9% | 0.0% || 2ms 0.1% | 0.0% | chunky_png/canvas/png_encoding.rb~102-145:5085-7303
ChunkyPNG::Canvas#palette | 51ms 1.6% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/canvas.rb~268-270:10089-10154
ChunkyPNG::Palette.from_canvas | 51ms 1.6% | 0.0% || 9ms 0.3% | 0.0% | chunky_png/palette.rb~63-68:2377-2629
ChunkyPNG::Palette#initialize | 42ms 1.4% | 0.0% || 30ms 1.0% | 0.0% | chunky_png/palette.rb~21-24:954-1074
SortedSet#initialize | 12ms 0.4% | 0.0% || 0ms 0.0% | 0.0% | lib/mri/set.rb~726-729:725-819
SortedSet#merge | 12ms 0.4% | 0.0% || 6ms 0.2% | 0.0% | lib/mri/set.rb~770-773:1759-1847
SortedSet#add | 6ms 0.2% | 0.0% || 6ms 0.2% | 0.0% | lib/mri/set.rb~741-745:1000-1169
ChunkyPNG::Palette#best_color_settings | 7ms 0.2% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/palette.rb~195-211:7150-7613
ChunkyPNG::Palette#opaque? | 3ms 0.1% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/palette.rb~88-90:3303-3369
SortedSet#each | 3ms 0.1% | 0.0% || 2ms 0.1% | 0.0% | lib/mri/set.rb~775-779:1850-2004
block in ChunkyPNG::Palette#opaque? | 1ms 0.0% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/palette.rb~89:3319-3361
ChunkyPNG::Color#opaque? | 1ms 0.0% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/color.rb~304-306:12410-12468
ChunkyPNG::Color#a | 1ms 0.0% | 0.0% || 1ms 0.0% | 0.0% | chunky_png/color.rb~296-298:12189-12237
ChunkyPNG::Palette#black_and_white? | 3ms 0.1% | 0.0% || 1ms 0.0% | 0.0% | chunky_png/palette.rb~104-106:3841-3940
SortedSet#each | 2ms 0.1% | 0.0% || 1ms 0.0% | 0.0% | lib/mri/set.rb~775-779:1850-2004
SortedSet#to_a | 1ms 0.0% | 0.0% || 1ms 0.0% | 0.0% | lib/mri/set.rb~781-784:2007-2116
ChunkyPNG::Palette#grayscale? | 1ms 0.0% | 0.0% || 0ms 0.0% | 0.0% | chunky_png/palette.rb~96-98:3570-3642
SortedSet#each | 1ms 0.0% | 0.0% || 1ms 0.0% | 0.0% | lib/mri/set.rb~775-779:1850-2004
ChunkyPNG::Chunk::ImageData.split_in_chunks | 19ms 0.6% | 0.0% || 7ms 0.2% | 0.0% | chunky_png/chunk.rb~255-259:9983-10267
rb_deflate_s_deflate | 12ms 0.4% | 0.0% || 4ms 0.1% | 0.0% | src/main/c/zlib/zlib.c~1622:44042-44097
rb_ensure | 5ms 0.2% | 0.0% || 1ms 0.0% | 0.0% | src/main/c/cext/ruby.c~2107:59266-59360
deflate_run | 4ms 0.1% | 0.0% || 0ms 0.0% | 0.0% | src/main/c/zlib/zlib.c~1589:43218-43240
zstream_run | 4ms 0.1% | 0.0% || 0ms 0.0% | 0.0% | src/main/c/zlib/zlib.c~1024:27867-27929
zstream_append_input | 1ms 0.0% | 0.0% || 0ms 0.0% | 0.0% | src/main/c/zlib/zlib.c~827:23738-23804
rb_str_buf_cat | 1ms 0.0% | 0.0% || 0ms 0.0% | 0.0% | src/main/c/cext/ruby.c~981:27520-27591
rb_str_cat | 1ms 0.0% | 0.0% || 0ms 0.0% | 0.0% | src/main/c/cext/ruby.c~882:24901-24968
rb_enc_str_new | 1ms 0.0% | 0.0% || 0ms 0.0% | 0.0% | src/main/c/cext/ruby.c~1301:37035-37101
Coverage #
The coverage tool reports coverage by statement, line, and root.
Root means the root of a function, i.e., how many methods and blocks were covered.
Enable it with --coverage:
-------------------------------------------------------------------------------------------------------------------------------------
Code coverage histogram.
Shows what percent of each element was covered during execution
-------------------------------------------------------------------------------------------------------------------------------------
Path | Statements | Lines | Roots
-------------------------------------------------------------------------------------------------------------------------------------
chunky_png-1.3.11/lib/chunky_png.rb | 100.00% | 100.00% | 100.00%
chunky_png-1.3.11/lib/chunky_png/canvas.rb | 58.40% | 69.41% | 35.90%
chunky_png-1.3.11/lib/chunky_png/canvas/adam7_interlacing.rb | 28.57% | 50.00% | 28.57%
chunky_png-1.3.11/lib/chunky_png/canvas/data_url_exporting.rb | 80.00% | 83.33% | 80.00%
chunky_png-1.3.11/lib/chunky_png/canvas/data_url_importing.rb | 57.14% | 70.00% | 80.00%
chunky_png-1.3.11/lib/chunky_png/canvas/drawing.rb | 8.28% | 44.02% | 13.33%
chunky_png-1.3.11/lib/chunky_png/canvas/masking.rb | 28.57% | 51.72% | 44.44%
chunky_png-1.3.11/lib/chunky_png/canvas/operations.rb | 42.42% | 65.07% | 21.95%
chunky_png-1.3.11/lib/chunky_png/canvas/png_decoding.rb | 52.84% | 68.27% | 26.98%
chunky_png-1.3.11/lib/chunky_png/canvas/png_encoding.rb | 44.44% | 62.07% | 40.43%
chunky_png-1.3.11/lib/chunky_png/canvas/resampling.rb | 17.46% | 48.51% | 25.00%
chunky_png-1.3.11/lib/chunky_png/canvas/stream_exporting.rb | 61.54% | 72.22% | 44.44%
chunky_png-1.3.11/lib/chunky_png/canvas/stream_importing.rb | 31.82% | 45.83% | 40.00%
chunky_png-1.3.11/lib/chunky_png/chunk.rb | 82.84% | 86.32% | 68.42%
chunky_png-1.3.11/lib/chunky_png/color.rb | 41.82% | 59.00% | 33.93%
chunky_png-1.3.11/lib/chunky_png/compatibility.rb | 75.00% | 66.67% | 75.00%
chunky_png-1.3.11/lib/chunky_png/datastream.rb | 83.56% | 87.50% | 80.00%
chunky_png-1.3.11/lib/chunky_png/dimension.rb | 42.11% | 62.07% | 23.08%
chunky_png-1.3.11/lib/chunky_png/image.rb | 85.00% | 90.32% | 90.00%
chunky_png-1.3.11/lib/chunky_png/palette.rb | 41.18% | 63.46% | 42.31%
chunky_png-1.3.11/lib/chunky_png/point.rb | 42.86% | 62.96% | 25.00%
chunky_png-1.3.11/lib/chunky_png/vector.rb | 40.98% | 63.10% | 10.34%
chunky_png-1.3.11/lib/chunky_png/version.rb | 100.00% | 100.00% | 100.00%
-------------------------------------------------------------------------------------------------------------------------------------
Debugging #
Debugging with VSCode #
This is the best-supported debugger for TruffleRuby, see this documentation.
Chrome Inspector #
GraalVM lets you debug Ruby programs, and any other language supported by GraalVM, using the Chrome DevTools Protocol to attach to debuggers such as Chrome Developer Tools.
Run with --inspect, open the given URL in Chrome, drag your file system into the sources list, and then set a breakpoint and resume execution.
Having the debugger attached and simple breakpoints set should not reduce performance.
NetBeans #
You can also debug GraalVM languages using NetBeans.
Run with --jvm --vm.agentlib:jdwp=transport=dt_socket,server=y,address=8000,suspend=y and attach to the process as if you were debugging a Java program.
Then click Toggle pause in GraalVM script (the pause icon with a G superimposed) and break, and you will break into the Ruby code.
You will see Ruby stack frames and local variables rather than Java stack frames and local variables.
