Atomic and Threadify

Ruby JRuby
1

I’m trying to use the Atomic and Threadify libraries, but I’m either
misunderstanding something somewhere or they don’t play nice together.
The output of the one liner below should be 166650, but the Atomic
updates look like they are being randomly missed sometimes:

jruby -rthreadify -ratomic -e
‘t=Atomic.new(0);(0…100).to_a.threadify(24){|n| n.times{|x|
t.update{|v|v+x}}};p t.value’
166727
jruby -rthreadify -ratomic -e
‘t=Atomic.new(0);(0…100).to_a.threadify(24){|n| n.times{|x|
t.update{|v|v+x}}};p t.value’
167145
jruby -rthreadify -ratomic -e
‘t=Atomic.new(0);(0…100).to_a.threadify(24){|n| n.times{|x|
t.update{|v|v+x}}};p t.value’
166814
jruby -rthreadify -ratomic -e
‘t=Atomic.new(0);(0…100).to_a.threadify(1){|n| n.times{|x|
t.update{|v|v+x}}};p t.value’
166650

Doing it without Threadify also seems to work:

jruby -ratomic -e
‘t=Atomic.new(0);a=(0…100).to_a;th=[];a.each{|n|th<<Thread.new(n){n.times{|x|t.update{|v|v+x}}}};th.each{|ths|
ths.join};p t.value’
166650

–
Alex G.

2

Seems as thread-ify is not “really” thread-safe.

I would try reporting if you really want to use it … but it’s not
really
battle tested (did not find tests).

Also you can simply use a java.util.atomic.AtomicInteger value if you
only
need to count atomically.

K.

3

Yeah, I always liked Threadify for super-simple threadification, but
it’s pretty old now. Using plain old Threads works for me, just wanted
to make sure I wasn’t misunderstanding something around Atomic’s
concurrency model.

AG

On 01.10.2013 13:58, Karol B. wrote:

On Tue, Oct 1, 2013 at 1:34 PM, Alex G. wrote:

t.update{|v|v+x}}};p t.value’
't=Atomic.new(0);(0…100).to_a.threadify(1){|n| n.times{|x|
Links:

[1] http://xircles.codehaus.org/manage_email
[2] mailto:[email protected]

–
Alex G.