Bug #8335: Performance regression with many threads

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.0.0p0 (2013-02-24 revision 39474) [x86_64-darwin12.3.0]
• Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN

[mperham (Mike Perham)]

I've created a simple case to reproduce a performance problem with Sidekiq. A customer is using 200 worker threads to process background jobs and finding it to be quite slow. To process 50,000 jobs, it takes Ruby 1.9.3 about 200 seconds. With Ruby 2.0, the time required is almost double. Please see instructions to reproduce the problem here:

https://github.com/mperham/sidekiq/tree/master/myapp#ruby-20-slowness-with-big-concurrency

[mperham (Mike Perham)]

I have some concern about #8211 so here's the info. Each VM was installed via rbenv.

ruby -v
ruby 1.9.3p374 (2013-01-15 revision 38858) [x86_64-darwin12.3.0]
ruby -e 'puts RUBY_DESCRIPTION, RbConfig::CONFIG["cflags"], RbConfig::CONFIG["CFLAGS"]'
ruby 1.9.3p374 (2013-01-15 revision 38858) [x86_64-darwin12.3.0]
-O3 -ggdb -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Werror=pointer-arith -Werror=write-strings -Werror=declaration-after-statement -Werror=shorten-64-to-32 -Werror=implicit-function-declaration
-g -O2 -Wno-error=shorten-64-to-32 -pipe

rbenv shell 2.0.0-p0
ruby -v
ruby 2.0.0p0 (2013-02-24 revision 39474) [x86_64-darwin12.3.0]
ruby -e 'puts RUBY_DESCRIPTION, RbConfig::CONFIG["cflags"], RbConfig::CONFIG["CFLAGS"]'
ruby 2.0.0p0 (2013-02-24 revision 39474) [x86_64-darwin12.3.0]
-O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Werror=pointer-arith -Werror=write-strings -Werror=declaration-after-statement -Werror=shorten-64-to-32 -Werror=implicit-function-declaration
-Wno-error=shorten-64-to-32 -pipe

[mperham (Mike Perham)]

Confirmed. I rebuilt 2.0.0 with RUBY_CFLAGS="-O3" and now performance is as good or better than 1.9.3. You may close this issue.

[nagachika (Tomoyuki Chikanaga)]

• Status changed from Open to Closed

Thank you for confirmation.

[bitsweat (Jeremy Daer)]

Mike - also fixed @ https://github.com/sstephenson/ruby-build/pull/351