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Ruby performance profiling Minsk, SaM Solutions, 2013 Presented by Alexey Tulia @AlexeyTulia, github.com/crible
| Date post: | 05-Jul-2015 |
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Ruby performance profiling
Minsk, SaM Solutions, 2013
Presented by Alexey Tulia
@AlexeyTulia, github.com/crible
Ruby. A programmer’s best friend
Ruby implementations
SLOW CODE
Reasons?
Garbage collection
Slow methods call
one iteration takes ~ 100ms
Garbage collection
Need one Gb?
Expect 128 GC calls!
You lose 128*0,1 = 12,8 sec
Allocated memory never returns to the system!
runs on every 8Mb of allocated memory
Garbage collection
More objects allocation -> more GC calls -> slow code
RUBY_HEAP_MIN_SLOTS=8000000
RUBY_GC_MALLOC_LIMIT=10000
Garbage collection tuning
performance patches
Ruby String performance
user system total real21 chars 0.250000 0.000000 0.250000 ( 0.247459)22 chars 0.250000 0.000000 0.250000 ( 0.246954)23 chars 0.250000 0.000000 0.250000 ( 0.248440)24 chars 0.480000 0.000000 0.480000 ( 0.478391)25 chars 0.480000 0.000000 0.480000 ( 0.479662)26 chars 0.480000 0.000000 0.480000 ( 0.481211)27 chars 0.490000 0.000000 0.490000 ( 0.490404)
Ruby String performance
Heap strings
Shared strings
Embedded strings
struct RString { long len; char *ptr;};
Ruby String performance
struct RString { long len; char * ptr; VALUE shared;};
struct RString { char ary[RSTRING_EMBED_LEN_MAX +1];}
RSTRING_EMBED_LEN_MAX = 23
Slow methods call
What can I do to improve performance?
Use C extensions or gems
Use plain SQL instead of frameworks
Use CPU and memory profiling
Use Rubinius or JRuby
THIS TALK IS ABOUT THE TOOLS
TO FIX THE ISSUES
BEFORE YOU REWRITE SH*T IN SCALA, PROFILE!
TOOLS FOR LINUX
LSOFSTRACELTRACE
TOOLS FOR CPU
Ruby-profperftools
perftools.rb
STRACE
trace system calls and signals
strace -cp <pid>strace -ttTp <pid> -o <file>
% time seconds uses/call calls errors syscall50,39 0,00064 0 1197 592 read
34,56 0,00044 0 609 writev
14,96 0,000019 0 1226 epoll_ctl
0,00 0,000000 0 4 close
0,00 0,000000 0 1 select
0,00 0,000000 0 4 socket
0,00 0,000000 0 4 4 connect
0,00 0,000000 0 1057 epoll_wait
100,0 0,000127 4134 596 total
strace -cp <pid>
LTRACEtrace dynamic library calls
ltrace -F <conf_file> -bg -x <symbol> -p pid
ltrace -F <conf_file> -bg -x <symbol> -p pid
-F <conf_file>
int mysql_real_query(addr,string,ulong);void garbage_collect(void);int memcached_set(addr,string,ulong,string,ulong);
ltrace -x garbage_collect
ltrace -x mysql_real_query
mysql_real_query(0x1c9e0500, "SET NAMES 'UTF8'", 16) = 0 <0.000324>mysql_real_query(0x1c9e0500, "SET SQL_AUTO_IS_NULL=0", 22) = 0 <0.000322>mysql_real_query(0x19c7a500, "SELECT * FROM `users`", 21) = 0 <1.206506>mysql_real_query(0x1c9e0500, "COMMIT", 6) = 0 <0.000181>
RUBY-PROFfast code profiler for Ruby
%self total self child calls name------------------------------------------------------------------------ 8.39 0.54 0.23 0.31 602 Array#each_index 7.30 0.41 0.20 0.21 1227 Integer#gcd 6.20 0.49 0.17 0.32 5760 Timecell#date 5.11 0.15 0.14 0.01 1 Magick::Image#to_blob
RUBY-PROF for CPU
KCachegrind
a tool for visualisation
http://kcachegrind.sourceforge.net
KCachegrind
KCachegrind
PERFTOOLS.RBgoogle’s performance tools for ruby code
CPUPROFILE=/tmp/myprof \
pprof --calgrind ./myapp /tmp/myprof
gem install perftools.rb
RUBYOPT="-r`gem which perftools | tail -1`" \ ruby my_app.rb
PERFTOOLS.RB
CPUPROFILE_REALTIME = 1
CPU/wall time
CPUPROFILE_OBJECTS = 1CPUPROFILE_METHODS = 1
Memory profilingGC::Profiler.report
module «objspace»
Ruby-prof
Out of the box in Ruby 1.9GC::Profiler.report
Out of the box in Ruby 1.9module «objspace»
Ruby-prof for memoryrvm install 1.9.3-p448 --patch railexpress
gem install ruby-prof
$ ruby-1.9.3-p448 test.rbThread ID: 14925700Fiber ID: 17378400Total: 3842.242188Sort by: self_time
%self total self wait child calls name 56.94 2187.766 2187.766 0.000 0.000 20000 String#chars 32.79 1259.953 1259.953 0.000 0.000 10000 Array#join 10.17 390.812 390.812 0.000 0.000 10000 Array#shuffle 0.01 3839.391 0.336 0.000 3839.055 1 Integer#times 0.00 1562.766 0.188 0.000 1562.578 10000
GDB.rb$ sudo gdb.rb 13074 GNU gdb (GDB) 7.0 Reading symbols from /usr/bin/ruby...done. Attaching to program: /usr/bin/ruby, process 13074 0x00007fa8b9cb3c93 in select () from /lib/libc.so.6
(gdb) ruby eval 1+2 2
(gdb) ruby eval Thread.list.count 17
(gdb) ruby objects classes 1 YAML::Syck::Resolver 1 SystemStackError 10 OptionParser::Switch::NoArgument
What should I remeber before CPU profiling?
Turn GC off (GC.disable)
do_smth is so slow!!!
Make it work
Make it right
Make it fast
When should I stop performance optimisation?
Premature optimization is the root of all evil(c) Donald Knuth
TOOLS MAKE PROFILING EASIER
LEARN THEM, USE THEM
Questions?
Thank you!
