1 Demonstrations of uobjnew. 2 3 4 uobjnew summarizes new object allocation events and prints out statistics on 5 which object type has been allocated frequently, and how many bytes of that 6 type have been allocated. This helps diagnose common allocation paths, which 7 can in turn cause heavy garbage collection. 8 9 For example, trace Ruby object allocations when running some simple commands 10 in irb (the Ruby REPL): 11 12 # ./uobjnew -l ruby 27245 13 Tracing allocations in process 27245 (language: ruby)... Ctrl-C to quit. 14 15 TYPE # ALLOCS # BYTES 16 NameError 1 0 17 RubyToken::TkSPACE 1 0 18 RubyToken::TkSTRING 1 0 19 String 7 0 20 RubyToken::TkNL 2 0 21 RubyToken::TkIDENTIFIER 2 0 22 array 55 129 23 string 344 1348 24 ^C 25 26 27 Plain C/C++ allocations (through "malloc") are also supported. We can't report 28 the type being allocated, but we can report the object sizes at least. Also, 29 print only the top 10 rows by number of bytes allocated: 30 31 # ./uobjnew -S 10 -l c 27245 32 Tracing allocations in process 27245 (language: c)... Ctrl-C to quit. 33 34 TYPE # ALLOCS # BYTES 35 block size 64 22 1408 36 block size 992 2 1984 37 block size 32 68 2176 38 block size 48 48 2304 39 block size 944 4 3776 40 block size 1104 4 4416 41 block size 160 32 5120 42 block size 535 15 8025 43 block size 128 112 14336 44 block size 80 569 45520 45 ^C 46 47 48 USAGE message: 49 50 # ./uobjnew -h 51 usage: uobjnew.py [-h] [-l {c,java,ruby,tcl}] [-C TOP_COUNT] [-S TOP_SIZE] [-v] 52 pid [interval] 53 54 Summarize object allocations in high-level languages. 55 56 positional arguments: 57 pid process id to attach to 58 interval print every specified number of seconds 59 60 optional arguments: 61 -h, --help show this help message and exit 62 -l {c,java,ruby,tcl}, --language {c,java,ruby,tcl} 63 language to trace 64 -C TOP_COUNT, --top-count TOP_COUNT 65 number of most frequently allocated types to print 66 -S TOP_SIZE, --top-size TOP_SIZE 67 number of largest types by allocated bytes to print 68 -v, --verbose verbose mode: print the BPF program (for debugging 69 purposes) 70 71 examples: 72 ./uobjnew -l java 145 # summarize Java allocations in process 145 73 ./uobjnew -l c 2020 1 # grab malloc() sizes and print every second 74 ./uobjnew -l ruby 6712 -C 10 # top 10 Ruby types by number of allocations 75 ./uobjnew -l ruby 6712 -S 10 # top 10 Ruby types by total size 76
