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+1 For the above mentioned book, especially if you are looking at computer systems/networks.

For more pragmatic treatment found "Fundamentals of Queueing Theory"[1] really good.

[1] http://mason.gmu.edu/~jshortle/fqt5th.html


Farnam Street curation is also good https://fs.blog/mental-models/


How far are we from "emergence" in terms of AI ecosystem ? Will quantum computing pave the way for it ?


Sorry, I don't know what "emergence" means in this context. If you mean AGI, I think (hope?) that we're still quite some ways away from it. Yes, quantum computing could help with AI -- for example through Grover's algorithm, which lets you solve many search, optimization, and planning problems in roughly the square root of the number of steps you would need classically. But it's a complicated story: many of the problems we care about will still be asymptotically hard even for quantum computers; conversely, as the spectacular recent achievements of deep learning and reinforcement learning (not to mention our own brains? :-) ) remind us, there's a great deal that can be done even with classical computers---often, outside the regime where we understand theoretically why the methods work. If you check back in 5 years or so, I'm optimistic that we'll know more about the applications of quantum computing to AI than we do right now.


"not to mention our own brains"

Is this a known known that our brain doesn't use QC?


No, it's an unknown known. :-)


This is very old, for a more recent version https://github.com/0xAX/linux-insides


One of my favorite guides on anything.


Not just the JVM, lot of libraries build thread pools based on number of processors and some of them even hard code the multipliers (X the number of processors etc).

Setting up each one becomes a lot of work fast, so we wrote a LD_PRELOAD[1] hook that overrides sysconf[1] _NC_PROCESSORS* call to get number of processors availabale/online to a certain specified value and is baked in the docker image by default during builds.

[1] http://man7.org/linux/man-pages/man3/sysconf.3.html


Can we expect that kind of horror to fade away as Java evolves?

In the .Net world there's the ThreadPool class to manage the single process-wide thread-pool, and the Task class to enqueue and orchestrate concurrent jobs (it uses ThreadPool and almost completely abstracts away the thread management).

(You could write your own thread-pool, of course, but for most code that wouldn't make sense.)

As I understand it, the JVM is rather behind in this department. (Not to mention async/await.)


> In the .Net world there's the ThreadPool class to manage the single process-wide thread-pool, and the Task class to enqueue and orchestrate concurrent jobs (it uses ThreadPool and almost completely abstracts away the thread management). > (You could write your own thread-pool, of course, but for most code that wouldn't make sense.)

Java had thread pools and tasks since 2004 (https://docs.oracle.com/javase/1.5.0/docs/api/java/util/conc...). For typical Java programs, no one is writing their own thread pool functionality as far as I know.


Java has these concepts too (ExecutorService since at least Java 5, circa 2004). The problem is not with the JDK libraries, it's been in the JVM's assumption that it's running on bare metal or a VM.

Linux containers leak information about the "true" environment in a way that upset JVM assumptions before 9 and 10.


.NET has the same problem: Each process would create one thread pool thread per CPU core, and you could end up with excessive context switching.

Java possibly makes it a bit easier to work around, really, in that Java forces you to initialize your thread pool, so it wouldn't feel quite so weird to add a "# of threads in thread pool" setting to an app config file for something. I'm guessing that's not the Docker way of doing it, though.


java.util.concurrent is actually more advanced that TPL, with contributions from Doug Lea.

Java just lacks async/await primitives.


java.util.concurrent certainly has more buttons and levers you can fiddle with. I could probably burn at least a week trying to grok the whole thing.


That's horrible and irresponsible; I love it.



Spanner secondary index link is broken correct one https://cloud.google.com/spanner/docs/secondary-indexes


Another excellent series on JVM perf/internals https://shipilev.net/jvm-anatomy-park/


This is not needed since version 1.6 See https://cbonte.github.io/haproxy-dconv/1.6/configuration.htm...

It can do DNS resolution at runtime, additionally you can override bunch of options as to how DNS resolution behaves in terms of TTL, Failures etc


There is an option added in 1.7 which makes old process exit after a grace period https://cbonte.github.io/haproxy-dconv/1.7/configuration.htm...


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