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NT 390 特價中
本課程從頭開始教導資料結構（linked lists，binary search trees，hash tables)。資料結構可以讓你應用程式提高效率，性能，速度和可擴展性。你將了解什麼是資料結構，為什麼它們是重要的，以及如何在 JavaScript 中編寫它們。你還將學習其它重要的程式設計概念，如遞歸，時間複雜度，“this” 關鍵字，prototype 物件，建構函數，因為資料結構非常自然地使用這些概念。本課程大量使用圖表和動畫來幫助更容易理解教材。
https://softnshare.com/learning-data-structures-in-javascript-from-scratch/
本文是一篇 2017 年的文章，雖然已經四年之久，但是我認為本篇文章值得一讀。
作者團隊於 2017 年時正在經歷如何將 VM 上的各種 Java 應用程式轉移到 Kubernetes 內的 Container，而本篇文章則是探討到底 Container 是如何透過 Linux Control Group 以及 namespace 實作的，透過對這些底層實作的瞭解，才有辦法針對 Container 效能部分去除錯與提升。
這種文章探討的都是很底層的概念，建議所有人都閱讀一遍，好好複習關於 cgroups/namespace 的概念，透過對這些概念的理解與掌握，能夠更有系統的去解釋何謂Docker Container，何謂輕量級虛擬化。
以下幫大家節錄一些重點，還是推薦自行閱讀全文
1. cgroup 用來隔離與限制 CPU,Memory,Disk,Network Bandwidth 等資源的用量
2. namespace 則是用來限制 ipc, pid, mount ,network, utc 等資訊的可視性，不同 namespace 內看到的資訊是獨立的，但是最終彼此還是屬於同一個 Kernel。
3. 任何沒有被 cgroup 規範的應用程式都會被自動包含到 root cgroup 的規範，不同發行版其位置不同，譬如 /sys/fs/cgropu.
假設今天透過 docker run 去運行一個 java 應用程式
a. Docker 會創建一個 pid namespace，接者運行 Java 前先把該應用程式給掛到新的 pid namespace 上並且賦予該 java 應用程式 PID 1
註: Host 上還是可以觀察到該 Java 應用程式，因為除了 Host 本身外，每個 pid namespace 都有自己的老爸，而老爸是可以看到小孩資訊的，這意味 docker dameon 雖然創建新的 pid namespace，但是host的pid namespace 實際是新 namespace 的老爸
b. 從老爸的視角來看，可以看到該 Java 應用程式也會有一個不同的 PID，而這個 PID 也會於 cgroup 系統中有自己的設定
4. CPU Cgroup 則是會用 share 為單位來定義每個 task 可以獲得多少相對的 CPU 時間，相對的算法是去計算 task 擁有的 share 數量佔了整個 cgroup 階層元件中的多少百分比。
舉例: 捨去其他服務單純考慮運行三個 Container 且有 4 Core CPU 的環境，三個 Container Task 分別給予 2048,1024,1024 share 的話，第一個 Container 大致是會被分配到兩個 CPU Time
5. CPU shares 沒有辦法去保證每個 task 最小用量是多少，所以需要透過 CPU Quotas 的概念來設定 CPU.cfs_quota_us(假設使用 CFS 這個排成演算法)以及 CPU.cfs_period_us(預設100ms)。
概念大概就是 cfs_period_us 定義的時間內，你最小可以使用多少時間，所以假如設定 cfs_quota_us 為 100ms，則預設情況下該 process 可以使用的量就是 100ms/100ms = 1 ~= 1 Core CPU
k8s 與上述的相關bug 可參考下列 issue
https://github.com/kubernetes/kubernetes/issues/67577
6. JVM 看到的是系統上全部的 CPU 資源，但是 Contaienr 本身當被限制 CPU 用量時，會有資訊落差，造成 GC 運行的效果不如預期，因為其認為系統有超多 CPU，而不知道自己其實被限制的CPU很少。
原文滿精彩的，推薦閱讀
https://engineering.squarespace.com/blog/2017/understanding-linux-container-scheduling
Score 6/10【新店小二, North Point, HK】This shop was for a short period inside 渣華道街市熟食市場 Java Road Cooked Food Centre, and back then had relations with Tung Po #東寶小館, hence its 二奶命 namesake. Nowadays they moved to few streets away & is finally independent.
#椒鹽鮮魷 Salt & Pepper Fried Calamari. A dish liked by both Hong Kongers & Expats alike, with beers. As much as I have always liked 店小二 since it's previous location, but, where the heck is the 椒鹽 part? 🤔 According to my experiences in HK & Overseas, there are a few interpretations. 1st of all, the #椒 referred to in this recipe is not necessarily White or Black pepper, but it can be the actual Green or Red Pepper. Think Spanish, Mexican, then Sichuan after 17th Century. Think Yuzu Kosho #柚子胡椒 , where the last part is also referring to an actual chopped pepper! Misnomer of subtle wordings in life, probably lost in translations even within local context
These days, 椒鹽鮮魷 in Hong Kong 🇭🇰 also tends to carry a drier fried Garlic part only, like 避風塘 Typhoon style. But according to what I remembered eating, back in the days, it was a semi-wet-dry condiment consisting of real chopped either red or green peppers, bits of garlic, salt, bit of white/black pepper, spring onions, probably more etc. Those were the good old days 😌😍
如果把鬥陣特工跟Undertale結合會變成什麼遊戲 !!
❤ 每天都有新影片!! 從今天起開始訂閱吧 !! ❤ ➔ http://bit.ly/Kouki
🔥 來看看【阿神】在使用的【實況裝備】有哪些超酷的東西：http://elgato.com/kouki 🔥
【影片製作團隊】
1) 剪輯師 ➔ AF
2) 字幕師 ➔ NatC
3) 封面製作師 ➔ Brocardo / BUUZ / Osla / KrepsStudio
4) 封面角色模組來源 ➔ https://www.minecraftforum.net/forums/mapping-and-modding-java-edition/minecraft-mods/2636433-undertale-mod-map-minecraft-1-10-2
5) 原作者 ➔ TobyFox
•⭐•⭐•⭐•⭐•⭐• Credits •⭐•⭐•⭐•⭐•⭐•
原作者 ➔ 天豹星雲 & 阿庫洛羅基亞
指令下載 ➔ https://forum.gamer.com.tw/C.php?bsn=18673&snA=183278&tnum=1
•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•
歡迎【提交你的自創麥塊地圖】：http://bit.ly/KoukiMaps
【Facebook】追蹤我 ➔ https://www.facebook.com/KamiKamiMatsu
【Twitter】追蹤我 ➔ https://twitter.com/Ashan_kouki
•⭐•⭐•⭐•⭐•⭐• License •⭐•⭐•⭐•⭐•⭐•
1) OMFG https://www.youtube.com/user/alexsavageomfg
Available at: http://bit.ly/meant4u
(as well as Spotify: http://bit.ly/meantforyou)
使用授權聲明 ➔ https://i.imgur.com/46j391z.jpg
2) D1ofAquavibe www.youtube.com/user/D1ofAquavibe
Available at: www.D1ofAquavibe.com/music
(as well as iTunes, Google Play, etc.)
使用授權聲明 ➔ https://i.imgur.com/Poykr3O.jpg
3) TheFatRat https://www.youtube.com/user/ThisIsTheFatRat
Available at: https://the-arcadium.net/
使用授權聲明 ➔ https://i.imgur.com/VL6htMz.png
4) Epidemicsound https://player.epidemicsound.com/browse/
使用授權聲明 ➔ https://i.imgur.com/BfoLOnN.jpg
5) FesliyanStudios https://www.fesliyanstudios.com/
使用授權聲明 ➔ https://i.imgur.com/K9Bs1sQ.jpg
6) Outro ➔ https://soundcloud.com/shurkofficial/haunted
使用授權聲明 ➔ https://i.imgur.com/c91ZARg.jpg
•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•
Microphone ➔ AT2020
Keyboard ➔ Ducky 青軸
Mouse ➔ D.Va Razer Abyssus Elite
#地下傳說 #Undertale #第一集
*If any producer or label has an issue with any of the uploads please get in contact (charlie615118@gmail.com) with me and I will delete it immediately (this includes artists of the images used).
Nearly 40% of the 700,000 migrant workers in Taiwan are from Indonesia. We speak to Nick Calpakdjian, producer of the feature-length documentary “Help Is On The Way” (2020) from Indonesia that explores the nuances of being domestic caregivers workers in Taiwan. Stories of these migrant workers begin at a nanny school in West Java.
“Help Is On The Way” won Best Feature Documentary at the 39th Indonesian Film Festival (FFI). It premiered in Taiwan in May on Public Television Station. International labor migration is a global issue, and this is The Taiwan Take. Guest-host today is Katherine Wei, a Taiwan-based journalist with The Strait Times. She is on Twitter @Katherinewei508.
Support us by donating on patreon.com/Taiwan | Follow us on Twitter @ghostislandme.
EPISODE CREDIT | Host, Katherine Wei | Producer, Emily Y. Wu @emilyywu | Editing, Eli Morimoto, Emily Y. Wu | a Ghost Island Media production | www.ghostisland.media
YOUTUBE
Support us on Patreon:
http://patreon.com/taiwan
Follow us on Twitter:
https://twitter.com/ghostislandme
SHOW CREDIT
Katherine Wei (Host / Research)
https://twitter.com/Katherinewei508
Emily Y. Wu (Producer / Editing)
https://twitter.com/emilyywu
Eli Morimoto (Editing)
Ghost Island Media (Production Company)
https://twitter.com/ghostislandme
www.ghostisland.media
MB01FRNJAWYTLFO
今天是我的生日，我們要來開著船來一場刺激的尬船吧 !!
❤ 每天都有新影片!! 從今天起開始訂閱吧 !! ❤ ➔ http://bit.ly/Kouki
🔥 來看看【阿神】在使用的【實況裝備】有哪些超酷的東西：http://elgato.com/kouki 🔥
•⭐•⭐•⭐•⭐•⭐• Credits •⭐•⭐•⭐•⭐•⭐•
原作者 ➔ Minecraft MineBoatRace
地圖下載 ➔ https://www.minecraftforum.net/forums/mapping-and-modding-java-edition/maps/2916746-minigame-mineboatrace-for-up-to-four-racers-and
•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•
【影片製作團隊】
1) 剪輯師 ➔ AF / Haya
2) 字幕師 ➔ 小綿羊
3) 封面製作師 ➔ Brocardo / BUUZ / Osla / KrepsStudio
使用授權聲明 ➔ https://i.imgur.com/fJyrLuq.jpg
歡迎【提交你的自創麥塊地圖】：http://bit.ly/KoukiMaps
【🔴直播頻道】➔ bit.ly/nonokouki
【Facebook】追蹤我 ➔ https://www.facebook.com/KamiKamiMatsu
【Twitter】追蹤我 ➔ https://twitter.com/Ashan_kouki
•⭐•⭐•⭐•⭐•⭐• License •⭐•⭐•⭐•⭐•⭐•
1) OMFG https://www.youtube.com/user/alexsavageomfg
Available at: http://bit.ly/meant4u
(as well as Spotify: http://bit.ly/meantforyou)
使用授權聲明 ➔ https://i.imgur.com/46j391z.jpg
2) D1ofAquavibe www.youtube.com/user/D1ofAquavibe
Available at: www.D1ofAquavibe.com/music
(as well as iTunes, Google Play, etc.)
使用授權聲明 ➔ https://i.imgur.com/Poykr3O.jpg
3) TheFatRat https://www.youtube.com/user/ThisIsTheFatRat
Available at: https://the-arcadium.net/
使用授權聲明 ➔ https://i.imgur.com/VL6htMz.png
4) Epidemicsound https://player.epidemicsound.com/browse/
使用授權聲明 ➔ https://i.imgur.com/BfoLOnN.jpg
5) FesliyanStudios https://www.fesliyanstudios.com/
使用授權聲明 ➔ https://i.imgur.com/K9Bs1sQ.jpg
6) Outro ➔ https://soundcloud.com/shurkofficial/haunted
使用授權聲明 ➔ https://i.imgur.com/c91ZARg.jpg
•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•⭐•
Microphone ➔ AT2020
Keyboard ➔ Ducky 青軸
Mouse ➔ D.Va Razer Abyssus Elite
#賽船 #划船 #競速
*If any producer or label has an issue with any of the uploads please get in contact (charlie615118@gmail.com) with me and I will delete it immediately (this includes artists of the images used).
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