Re: System.arraycopy vs Arrays.copyOf

Hi Carl, Did you read this: https://shipilev.net/blog/2016/arrays-wisdom-ancients/ ? :) Cheers On Thursday, February 9, 2017 at 5:33:12 PM UTC+1, Carl Mastrangelo wrote: > > Hi, > > I'm trying to copy an array of bytes and return the copy. I noticed that > there are two ways of doing this:

Re: Systematic Process to Reduce Linux OS Jitter

Hi, Those servers seem nice, but there is a huge no-go for us and our workload: There is only one socket. The actual CPUs have a L3 cache that is shared among cores, so depending on your workload other processes & threads can pollute this level of cache. In our application this pollution cause

Re: JVM with 100 seconds minor GC

Hi, I already experienced this issue with ParNew Collector: pause time is increasing between each GC and CPU is 100% consumed by GC threads. For me this is a bug in this collector in a very specific case. The case can be very reproducible but unfortunately, when we encounter this, the

Re: Linux isolcpus versus cgroup approach for isolating busy wait message processing threads

Hello More precisely it is cpuset instead of of cgroups The issue with isolcpus is that you are completely isolated from the OS scheduler. If you are guaranteed that there will be one and only one thread (with thread affinity) it's ok. However if more than one thread will be assigned to this

Re: Exclusive core for a process, is it reasonable?

Hi John, As always, it depends :) In my previous job, We had a system that processing orders in 100us. Here thread affinity and core isolation were mandatory to achieve the SLA. The difference measured was from 2x to 4x. But not all systems need this setting/tuning. if you are accessing a lot of

Re: Happens before between putting and getting from and to ConcurrentHashMap

Hello Vladimir, On Sunday, November 18, 2018, Vladimir Sitnikov wrote: > > > In this case that contract is provided by JLS "17.4.3. Programs and > Program Order" and "17.4.5. Happens-before Order" . > TL;DR: "If x and y are actions of the same thread and x comes before y in > program order, then

Re: Happens before between putting and getting from and to ConcurrentHashMap

Thanks Vladimir for your thoroughly explanation, I need to re read the Aleksey's JMM pragmatics 10 times more I guess  On Sun, Nov 18, 2018 at 7:35 PM Vladimir Sitnikov < sitnikov.vladi...@gmail.com> wrote: > Jean-Philippe>is a write to value but no read of this value inside the > same thread,

Re: UseNuma disables itself for no adequately explained reason

Hi Ben, Parallel GC supports Numa, but I'm not sure about G1! Cheers On Tuesday, August 27, 2019, Ben Evans wrote: > Hi, > > I've encountered an issue whereby, despite -XX:+UseNuma being > explicitly set on the command line, the final flags list that is seen > has it disabled. This is on

Re: Where has PrintGCApplicationStoppedTime gone?

Hi Try -Xlog:safepoint Regards On Thursday, May 14, 2020, Wojciech Kudla wrote: > Hi, > > While evaluating different post-java 8 JVMs I noticed that > PrintGCApplicationStoppedTime > is an unsupported option now. > According to Chris Newland's awesome list of JVM options >

Re: Long unexplained time-to-safepoint (TTSP) in the JVM

Hi Zac, I would suggest to use JFR to collect events about safepoints/VM Operations. for that you can upgrade to Zulu with at least 8u212 which includes JDK Flight Recorder (JFR). JFR is bundle into Oracle JDK 8 but with commercial license (but maybe you have subscribed, in this case, just enable