From: alexandre@...
Date: 2014-07-09T01:28:31+00:00
Subject: [ruby-core:63596] [ruby-trunk - Bug #10009] IO operation is 10x slower in multi-thread environment

Issue #10009 has been updated by Alexandre Riveira.


My application is not web-site is an ERP. So reporting and very heavy tasks are performed. Then the system crashes because only one thread using 100% cpu will damage the whole worker, passing any request for at least 2 seconds, then the requests go piling.
The key point is a thread using 100% of cpu will make all worker threads just make a few requests for postgres.

Ruby Without GVL is that possible??

I believe python works best because it uses part of another cpu (160%) to manage all the threads.
Doing the same test with pypy it uses 100% cpu as ruby and presents the same problems as ruby.

----------------------------------------
Bug #10009: IO operation is 10x slower in multi-thread environment
https://bugs.ruby-lang.org/issues/10009#change-47649

* Author: Alexandre Riveira
* Status: Open
* Priority: Urgent
* Assignee: 
* Category: 
* Target version: 
* ruby -v: ruby 2.1 x ruby 1.9.2 with taskset
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
I created this issue #9832 but not have io operation.
In the script attached I simulate IO operation in multi-thread environment.
For ruby 1.9.2 apply `taskset -c -p 2 #{Process.pid}` for regulates threads behavior.
The second Thread is a io operation

My results:

1) ruby 2.1.2
first 43500194
second 95
third 42184385

2) ruby-2.0.0-p451
first 38418401
second 95
third 37444470

3) 1.9.3-p545
first 121260313
second 50
third 44275164

4) 1.9.2-p320
first 31189901
second 897 <============
third 31190598

Regards


Alexandre Riveira


---Files--------------------------------
teste_thread_schedule_2.rb (1.05 KB)
teste_thread_schedule.py (953 Bytes)
teste_thread_schedule.rb (955 Bytes)
test_thread_sched_pipe.rb (1.01 KB)


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