From: alexandre@...
Date: 2014-07-11T20:34:57+00:00
Subject: [ruby-core:63669] [ruby-trunk - Bug #10009] IO operation is 10x slower in multi-thread environment

Issue #10009 has been updated by Alexandre Riveira.


Eric Wong wrote:
> 
> Lowering TIME_QUANTUM_USEC (in thread_pthread.c) helps with the I/O case
> (try it yourself if you have a 1000HZ kernel); but hurts overall
> throughput.

Hello Eric!!!!

I stayed enjoyed the result of change TIME_QUANTUM_USEC. Changed its value to 1000 only see the results:

ruby 2.
first 17434583
second 2754 <=============
third 16752441

If you have any problems I will try 10 * 1000.

It seems incredible because there was no need to apply taskset.
As this is a microbenchmark'll do the tests and if all goes well put into production. After I report news.


----------------------------------------
Bug #10009: IO operation is 10x slower in multi-thread environment
https://bugs.ruby-lang.org/issues/10009#change-47723

* 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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