Browsing the tag jvm
G1 Garbage Collector Considered Slow?
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(1 votes, average: 5.00 out of 5)
Loading ...I was recently considering trying out the new G1 garbage collector, see if it was any better than current real time CMS garbage collector. A concurrent soft real-time garbage collector that can compact? Awesome!
I switched one of my production applications to use the new G1 garbage collector and noticed a spike in CPU and diminishing throughput almost instantaniously, what gives? I googled around and stumbled upon this blog post and decided to do my own benchmarking.
I hacked up the following scala script based off the blog post to compare the two garbage collectors. The JDK that was used was JDK7u3 on Solaris on a quad core box.
CMS:
time scala -J-XX:+UseConcMarkSweepGC GC.scala
real 0m12.477s
user 0m12.364s
sys 0m0.491s
G1:
time scala -J-XX:+UseG1GC GC.scala
real 2m26.121s
user 7m33.234s
sys 0m10.888s
Conclusion:
Just what I saw with my production application, the throughput substantially diminished and the CPU cores spiked. I won’t be using the G1 garbage collector any time soon, hopefully Oracle will improve the G1 garbage collector with subsequent releases.
MogileFS Client on JRuby!
Leave a comment | Filed under programming (1 votes, average: 5.00 out of 5) Loading ...Are you running JRuby in production? Do you want distributed file storage for your “enterprise” application? Look no further, MogileFS is here.
MogileFS-Client has compatibility issues with JRuby due to it’s use of the low level Socket class. JRuby 1.5-dev does not yet support all the Socket methods, so here is a monkey patch to get the ruby mogilefs client working on JRuby. Yes it blocks, but who cares JRuby has native threads.
This is exactly why I love Ruby; monkey patching.
def self.mogilefs_new(host,port,timeout=5.0)
TCPSocket.open(host,port,timeout)
end
end
class TCPSocket
attr_accessor :mogilefs_addr, :mogilefs_connected, :mogilefs_size, :mogilefs_tcp_cork
def self.open(host,port,timeout = 5.0)
super(host,port.to_i)
end
def readable?
true
end
def write_nonblock(data)
write(data)
end
def recv_nonblock(size,arg)
recv(size,arg)
end
def mogilefs_init(host = nil, port = nil)
true
end
end
Here is an example test case on how to get it all to work.
require ‘mogilefs’
# jmogilefs.rb is the monkey patch above
# load it after loading mogilefs client.
require ‘jmogilefs.rb’
mg = MogileFS::MogileFS.new(:domain=>‘testserv’,:hosts=>[‘xxx.xxx.xxx.xxx:6001′])
p mg.get_file_data ‘video:100:default.jpg’
p mg.get_paths ‘video:100:default.jpg’,true
mg.list_keys(‘video:100′)[0].each do |f|
p f
end
