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View my-debug.md

I write a buggy server to leak socket fd, which listen on 5000, and as expected there were CLOSE-WAIT left when client is closed

$ ss -ntpa | grep 5000
LISTEN     0      50                       :::5000                    :::*      users:(("java",14586,92))
CLOSE-WAIT 79     0          ::ffff:127.0.0.1:5000      ::ffff:127.0.0.1:55804  users:(("java",14586,96))
CLOSE-WAIT 79     0          ::ffff:127.0.0.1:5000      ::ffff:127.0.0.1:59235  users:(("java",14586,93))
CLOSE-WAIT 5      0          ::ffff:127.0.0.1:5000      ::ffff:127.0.0.1:55803  users:(("java",14586,95))
CLOSE-WAIT 150    0          ::ffff:127.0.0.1:5000      ::ffff:127.0.0.1:59236  users:(("java",14586,94))
View CacheLineEffect.java
package benchmark;
public class CacheLineEffect {
//考虑一般缓存行大小是64字节,一个 long 类型占8字节
static long[][] arr;
public static void main(String[] args) {
arr = new long[1024 * 1024][];
for (int i = 0; i < 1024 * 1024; i++) {
arr[i] = new long[8];
View hystrix_circuit_bug.java
package hystrix;
import com.netflix.hystrix.*;
import rx.Observable;
import java.io.IOException;
import java.util.Random;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
View specter-benchmark.clj
(ns demo.specter-benchmark
(:use [com.rpl.specter]
[criterium.core]))
;; one big app state, look like
;; {app-id1 {peer-id1 #{ch-di1}}}
(def clients (atom {}))
(def num-app 10)
(def num-peer 20)
View trrprefs.md

Preferences

All preferences for the DNS-over-HTTPS functionality in Firefox are located under the "network.trr" prefix (TRR == Trusted Recursive Resolver).

network.trr.mode

set which resolver mode you want.

0 - Off (default). use standard native resolving only (don't use TRR at all)

1 - Race native against TRR. Do them both in parallel and go with the one that returns a result first.

View transducer_bench.clj
(def dataset (interleave (range 10000000) (range)))
(defn workflow [ds]
(->> ds
(dedupe)
(map #(* % %))
(filter #(= 0 (rem % 111)))
(take 10)))
View map_defrecord_bench.clj
(ns demo.record
(:require [criterium.core :refer [bench with-progress-reporting]]))
(def a-z-ks (map (comp keyword str) (seq "abcdefghijklmnopqrstuwvxyz")))
(def dummy-map (zipmap a-z-ks (range)))
(defmacro alphabet-macro []
`(do
(defrecord ~'Alphabet [~@(map (comp symbol str) a-z-ks)])
(def ~'dummy-record (~'Alphabet. ~@(range 26)))))
@jiacai2050
jiacai2050 / CacheTest.java
Created Sep 6, 2017
guava caffeine 性能测试
View CacheTest.java
import com.github.benmanes.caffeine.cache.Caffeine;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.yahoo.ycsb.generator.NumberGenerator;
import com.yahoo.ycsb.generator.ScrambledZipfianGenerator;
import junit.framework.TestCase;
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadInfo;
import java.text.NumberFormat;
@jiacai2050
jiacai2050 / gist:13b1b45af7349a3ff6d2a79bdd37f7f5
Created May 16, 2017 — forked from daviesian/gist:4517859
Code to redirect output nrepl output to a particular client repl.
View gist:13b1b45af7349a3ff6d2a79bdd37f7f5
;; After connecting an nrepl client repl to an nrepl server, some
;; output will still appear on stdout from the server.
;; Try these snippets - they will both produce output on the nrepl server
;; Java libraries commonly do both these things.
(.println System/out "Hello stdout.")
(.start (Thread. #(println "Hello from a new thread.")))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@jiacai2050
jiacai2050 / 0. description.md
Created Nov 21, 2016 — forked from Integralist/0. description.md
Clojure deftype, defrecord, defprotocol
View 0. description.md
  • defprotocol: defines an interface
  • deftype: create a bare-bones object which implements a protocol
  • defrecord: creates an immutable persistent map which implements a protocol

Typically you'll use defrecord (or even a basic map);
unless you need some specific Java inter-op,
where by you'll want to use deftype instead.

Note: defprotocol allows you to add new abstractions in a clean way Rather than (like OOP) having polymorphism on the class itself,

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