S***s
发帖数: 104 | 1 spring boot copy dropwizard, both are sync MICROservices model
if u're already familiar with spring go with spring boot
dropwizard camp has many spring haters, calling spring enterprisy
vertx is in the reactive real microservices camp, competing against AKKA,
Quasar, rxjava, https://github.com/aol/micro-server etc |
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w***g
发帖数: 5958 | 2 这个我没有研究过。我做的东西OS threads足够用了。
我不知道fiber/go-routine这些对实际系统帮助有多大。
一般来说用thread的系统和用fiber的系统本身设计上
就有很大的不同。一个系统本身用fiber写，然后换成
thread后性能下降很大，或者一个系统本身用thread
写，换成fiber后性能下降很大都有可能。
对于大部分人人，我建议OS thread就足够了。如果有
瓶颈，一方面是从I/O开销调，改进I/O pattern，上
更快的SSD，另一方面是数据库索引和查询优化。
操作系统在context switch上面的这点开销和上面两个
比都是微不足道的。如果上面这两个出了问题，改
fiber对提高性能不会有帮助。相反，因为fiber是
cooperative的，程序写得不小心可能会导致系统挂起，
而且调试起来会非常啰嗦。(OS thread可以直接
打印call stack。Go是语言支持，应该也没问题。
Quasar就不知道了。C/C++也有fiber实现，想要调试
那是不可能的。） |
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s***o
发帖数: 2191 | 3 quasar一直没火起来，除了没有大公司在背后推手，我觉得更主要的就像你说的，没有
非要用它的合适场景。这个我就先扔一边不看了。谢谢 |
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c******n
发帖数: 16666 | 4 RN我几个月前配置环境就吐了 貌似后来的更新改良了这部分 不过我没继续试下去
ionic配合ng还是可以做的 启动还是有点慢就是 ng1的时候做过一个 ng2之后没用过
vue的话 有个阿里搞得weex，但是我看了他官网那个样子就觉得起码还得等个一年半载
最近准备试一下Quasar，也是配合vue，里面还是用cordova，不过一般的app也够了，
真的复杂了还是上真native比较好 |
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z****e
发帖数: 54598 | 7 尝试着回答一下这个问题
1）做不到比os native的更好，但是问题在于，有些操作系统根本就没有cooperative
sheduling，比如linux，如果有的话，直接做一层包装就好了，但是没有的话，就只能
让语言来做了
2）不靠机器码，但是靠字节码，基本上就差不多了，光靠当前java的api，是不够的，
需要加多一个context参数，参考kotlin的coroutine实现，或者是通过java agent_织
入_一些context代码，这就是quasar的实现，这也是loom名称的由来
3）强在哪里呢
嗯，这个说来话长，说说我的理解
wdong有一篇回帖，解释了os层面cooperative scheduling和preemptive scheduling的
区别，有空自己去找，但是我觉得他说得复杂了，当然也因为后来用户层面框架的发展
，比如actor model有关系，看看我能不能解释清楚，这一块涉及的东西太多，os&jvm
和vert.x/actor model乃至开发者自身，都有需要配合的部分，任何一个部分不能掉链
子，所以解释起来不容易
先说os&jvm层面，这个是... 阅读全帖 |
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s***o
发帖数: 2191 | 8 这么多回帖，还以为又打起来了。我觉得这个project意义还是很大的，quasar早就有
人在用了。但是因为要挂agent，做bytecode manipulation，很多人有顾虑。如果有了
jvm level native support，估计会有新一堆的framework出来。 |
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z****e
发帖数: 54598 | 9
经常
停止这种无意义的blablabla吧？
我们上点能够测量的
我就这么说vert.x+java性能可以超过go，vert.x+kotlin应该也行
但是会略弱于vert.x+java，但是可读性会超过vert.x+java（现阶段）
其次vert.x&go不管在什么时候，都可以吊打其他任何一个同步api的系统
用异步或者协程肯定比同步快，快很多，尤其是在io bound的时候
再来，我们可以保证，用vert.x，可以把用户线程控制在很少量的几个上
具体是cpu available cores * 2
比如1core就是2个线程就够了
再来，在线程数有限的前提下，coroutine要做的事很少，就是suspend&resume
我相信go的coroutine要做的更多
木有错，所以go很有可能做得不好，所以性能比不过vert.x
说这些，都需要证据，不要没事blablabla，证据就在这里
https://www.techempower.com/benchmarks/#section=data-r14&hw=ph&test=json
我个人认为啊，vert.x和异步，再加上coro... 阅读全帖 |
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z****e
发帖数: 54598 | 10 你要看什么？
不用等5年
现在已经有了
早就有了
http://vertx.io/docs/vertx-sync/java/
https://github.com/puniverse/quasar
你说java做不出来？现有的东西出不来？
现在一大票语言都开始async／await，coroutine什么都出来了
你想等5年之后？等什么？等这些语言一个个做出来嘛？
现在已经有好几个了，比如kotlin，你是说这个东西不存在？
说了，不是你想的那种coroutine，你被wdong绕进去了
wdong说的那种coroutine不是我们需要的coroutine或者说不是那么复杂的东西
我们只需要其中一小部分，就能满足要求了
用工具的目的是用来解决问题的，不是用来探索真理的
你要探索宇宙的真相，大可以去物理学上咕哝上半天
反正买买提每次讨论物理都很热闹
我们要处理的是怎么榨取机器性能，同时保证可读性不要下降 |
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s******o
发帖数: 298 | 12 By SPACE.com Staff
posted: 12:23 pm ET, 22 April 2002
Researchers have found a possible source for enigmatic high-energy particles
called cosmic rays in a study that shows rapidly spinning black holes may act
as giant batteries, shooting particles into the cosmos at nearly the speed of
light.
The study involved four aged galaxies that used to be among the brightest
beacons in the universe but are now somewhat worn out. These former quasars,
as they would have been called, might help solve a long |
|
s*****t
发帖数: 1994 | 13 Black holes, like ill-mannered diners, let out a belch after wolfing down a meal. Now for the first time,
an astronomer says he has detected this cosmic burp--in the form of gas rapidly escaping a black
hole that has just swallowed a star.
The biggest appetites belong to quasars--supermassive black
holes at the cores of distant galaxies. As gas and stars are
violently sucked in |
|
s*****t
发帖数: 1994 | 14 SEATTLE--Do gravity's tentacles cross space at the speed of light? Albert Einstein thought so, and two scientists now claim to have proved him right. Their results, described as the first measurement of gravity's speed, is based on observations of
Jupiter bending the light from a quasar. However, some physicists think the research--announced here on 7 January at a meeting of the American Astronomical Society--has fatal flaws.
Isaac Newton thought gravity acted instantaneously, but Einstein's gen |
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s*****t
发帖数: 1994 | 15 NGC 613: Spiral of Dust and Stars
Credit: M. Neeser (Univ.-Sternwarte M|nchen), P. Barthel (Kapteyn Astron. Institute), H. Heyer, H. Boffin (ESO), ESO
Explanation: When morning twilight came to the Paranal Observatory in Chile, astronomers Mark Neeser and Peter Barthel interrupted their search for faint quasars, billions of light-years away. And just for a moment, they used Very Large Telescopes at
the European Southern Observatory to appreciate the beauty of the nearby Universe. One result was |
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S***n
发帖数: 330 | 16 http://news.yahoo.com/most-extreme-space-discoveries-2012-12084
Astronomical discoveries in 2012 have reshaped what we know about the
universe and pushed some instruments to the very limits of their observing
power.
Scientists discovered a galaxy that harbors an enormous central black hole
17 billion times more massive than the sun. Another research group spotted a
scorching-hot rocky planet in the closest star system to our own. Meanwhile
,the records for most massive galaxy cluster and most di... 阅读全帖 |
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D***s
发帖数: 5613 | 18 以前还以为是white hole呢
现在都是黑洞主导的 |
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D***s
发帖数: 5613 | 20 以前还以为是white hole呢
现在都是黑洞主导的 |
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a***e
发帖数: 27968 | 21 喷流垂直吸积盘是怎么带走角动量的？
如果流矢经过转动中心，这个流的角动量为零
如果流矢不经过中心，这个角动量是平行吸积盘的
和吸积盘带来的垂直吸积盘的角动量就是正交的，还是不妥
另外，好像这个流矢是沿中心天体磁轴的，和自转轴/吸积面可以有个夹角
脉冲星这个大陀螺好像就是这样 |
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D********i
发帖数: 103 | 22 一般认为喷流有自旋。喷流只是aspect ratio特别大，但并不是无穷大，喷流里面有限
半径处的物质是可以就角动量的
目前有理论认为喷流就是纯流体力学，但是很多人认为和磁场关系很大，喷流里面应该
有非常强的缠绕在一起的磁场，磁场的起源还不太清楚，可能是来源于吸积盘，可能是
来源于中心天体。但是中心天体是黑洞的话就没有磁场了。喷流一般是垂直于吸积面的
，但是也有不太垂直的，可能是磁场共同作用的结果。中心天体自转轴倒不一定一定垂
直于吸积盘。不过如果长期吸积的话，吸积物质的角动量应该会慢慢带动自转轴垂直于
吸积盘 |
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z**********e
发帖数: 22064 | 23 【书讯: 在方励之先生去世两周年之际，《方勵之紀念文集》（科學卷），由明鏡出版
社出版了。全书收集了74篇不同作者的回忆文章。作者中有方先生的尊师，亲朋好友，
工作中的同事，科研中的合作者，以及方先生不同时期的学生。全书共556页，并收集
了许多作者和方先生的合影，方先生的手迹等照片。书中也列出了方先生所发表科研论
文的目录。《方勵之紀念文集》是缅怀方先生，研究方先生的一部重要的书籍。】
方励之老师曾跟我说，他是科大建校（1958年）时最早的一批教师之一。我是1962年考
入中国科技大学的，但是，我同方励之老师的相识却不在我读书期间，地点也不在北京
玉泉路的校园里。那时我是近代力学系的学生，普通物理课是由物理教研室的老师来上
，但是他没有被安排给我们授课，无缘相识。
最初注意到方励之的名字，好像是在1973年。那一年，我离开学校已有五年，在昆明钢
铁厂已经当了三年烧锅炉的工人。当时厂里买了一台日本进口的扫描电子显微镜，为了
翻译它的英文说明书，把我从车间调到厂技术处的资料室，这使我有机会接触到一些中
外文的科技资料。此时，1971年9月发生的林彪外逃事件已经过去两年，文化大革命已
成强... 阅读全帖 |
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m*********k
发帖数: 10521 | 24 "[Military]TempBM Oct 31. ● （过十万，再接再励！）众志成城，白宫请愿
签名需要你"
成功奖励 50 伪币的用户: CATCAT, fourriver, ptx, Doser, IV, rebecca1975, PT,
huyanke, allence, ilovqianqian, AnyMoreLeft, laoshu09, hahaha2012, hj630,
TempBM, happymyt, OldLady80, shinn, davidcrazy, cathy1061, MMT007, shenms,
shouben, cassfs, wxu121, acrophoenix, mimi12, xxmj, xuxuaiying, pplar,
chuweitong, easy0784, bluepen, cj1208, sunnyy, nmstarry, bingbing01,
juliemzhu, iruka, xiaose, rooster, acespade, crasher, mit09, xinchong,
jonsun, hyp... 阅读全帖 |
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m*********k
发帖数: 10521 | 25 "[SanFrancisco]fatcat Jun 17 ● 【发双黄包子】庆祝勇士拿到NBA总冠军"
扣除版面:(SanFrancisco)2540伪币成功
成功奖励 20 伪币的用户:?fatcat, maxima, alaskaforfun, recursive, catbertsf,
kukutf, PigHead5, z00, shao2010, Dulcedo, lagoons, weee, netmn, surefirer,
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vangogh333, smallrriver, oliver0118, bbpp2010, happynewlife, mja, gisflow,
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, ItachiUchiha, crystal863, ffmx, tomato0918, M... 阅读全帖 |
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m*********k
发帖数: 10521 | 26 "[PhotoGear]
poise Sep 28 ● 50个月饼"
成功奖励 10 伪币的用户: DRGX3, yzb, marketscale, jazztech, dddddddd,
mitbbsfan, takami, sunxh163, mondler, bmwcar, Alexandrio, logic98,
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sunboy30860, TheSun, denver, daysunny, houmitbbs, Yobi, foxulee, sxgva,
seashore, Rains, sponge, fathair
成功扣除 5... 阅读全帖 |
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w*******y
发帖数: 60932 | 27 Detailed Specs:Intel Core i7 740QM Quad Core Processor, 1.73GHz (2.93GHz
Turbo Mode, 6M Cache
1GB DDR3 ATI Radeon Mobility HD 5730
15.6-inch WideHD+ 1600x900 (900p) WLED
6GB Memory (1x 2GB, 1x 4GB DDR3)
320GB SATAII 7,200RPM
Slot-Load Dual Layer DVD Burner (DVD+-RW, CD-RW)
Primary - 6-cell (56Watt) Lithium-Ion Battery
Wireless 1520 802.11n Half Mini-Card
1 Year Basic Service Plan
Alienware M15x, Lunar Shadow
AlienFX Quasar Blue
Alienhead 3D
Steam and Portal Factory Installed
Internal High-Defini... 阅读全帖 |
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w*******y
发帖数: 60932 | 28 Alienware laptops are typically expensive but seems pretty good price
especially for this configuration.
[Linky:
http://configure.us.dell.com/dellstore/config.aspx?c=us&l=en&cs=19&kc=&oc=DKPDFV3
]
Alienware M15x ($1,724.00)
Free Radeon HD 5850 Upgrade (-$150.00)
Instant discount (-$225)
Coupon (-$50)
Total 1299.00 + Tax + FS
$50 off coupon code - BHW1L0MX0D?MCX
[specs]
Genuine Windows7 Home Premium, 64bit, English
Alienware M15x, Cosmic Black
IntelCore i7 740QM Quad Core Processor, 1.... 阅读全帖 |
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w*******y
发帖数: 60932 | 29 All active duty military/reserve/veterans can get the following laptop new
from Dell for $880.83 with free shipping and no tax through AAFES.
First go to Link:
https://shop.aafes.com/shop/Default.aspx
and either log in or create a new account.
Then go to Computers -----> Notebooks
Then click on Specialty Store: Dell Notebook Assortment!
Then click on the *To shop Dell, please click here* area
A pop-up will pop up and you need to click on CONUS shipment
Scroll down and click on the ALIENWARE la... 阅读全帖 |
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w*******y
发帖数: 60932 | 30 Hope it is not a re-post.
EPP deal:
Link:
http://configure.us.dell.com/dellstore/config.aspx?c=us&cs=6099
Coupon code: VR?90Z?B3RCT9X
Without Bluetooth.
Do not ask again: No requirement for Epp. Dell did not verify any
information you provided. Just click the link above and checkout, use the
coupon, and you will get it finally 636.02+tax!
Configuration:
Genuine Windows7 Home Premium (64-bit)
IntelCore i5 520UM (3M Cache, 1.066 GHZ with 1.866 GHz Max Turbo Frequency
) - Overclockable
8GB Dual Cha... 阅读全帖 |
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m*********k
发帖数: 10521 | 31 成功奖励 20 伪币的用户: sohappygg, clapman, CZ19541955, mayomi, baddino, zhanglaosan, verithas, sandywolf, sspanzer, withoutacar, Satine, fengzu101, NiuBi, caoxiaonan, actuary616, JackBlack, iamtheretoo, miaomi, vinhelp07, purplerain88, wxx033000, steedwang, xuechn, mikef, mark, saintknight, kksb, gregoryhouse, modaya, modaya, graceshcn
奖励版面:(Military)100伪币失败 原因:版面现金超过正极限值
奖励版面:(NextGeneration)60伪币成功
奖励版面:(WaterWorld)60伪币成功
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奖励版面:(Returnee)40伪币成... 阅读全帖 |
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s******o
发帖数: 298 | 32 By SPACE.com Staff
posted: 12:23 pm ET, 22 April 2002
Researchers have found a possible source for enigmatic high-energy particles
called cosmic rays in a study that shows rapidly spinning black holes may act
as giant batteries, shooting particles into the cosmos at nearly the speed of
light.
The study involved four aged galaxies that used to be among the brightest
beacons in the universe but are now somewhat worn out. These former quasars,
as they would have been called, might help solve a long |
|
s*****t
发帖数: 1994 | 33 Black holes, like ill-mannered diners, let out a belch after wolfing down a meal. Now for the first time,
an astronomer says he has detected this cosmic burp--in the form of gas rapidly escaping a black
hole that has just swallowed a star.
The biggest appetites belong to quasars--supermassive black
holes at the cores of distant galaxies. As gas and stars are
violently sucked in |
|
s*****t
发帖数: 1994 | 34 SEATTLE--Do gravity's tentacles cross space at the speed of light? Albert Einstein thought so, and two scientists now claim to have proved him right. Their results, described as the first measurement of gravity's speed, is based on observations of
Jupiter bending the light from a quasar. However, some physicists think the research--announced here on 7 January at a meeting of the American Astronomical Society--has fatal flaws.
Isaac Newton thought gravity acted instantaneously, but Einstein's gen |
|
s*****t
发帖数: 1994 | 35 NGC 613: Spiral of Dust and Stars
Credit: M. Neeser (Univ.-Sternwarte M|nchen), P. Barthel (Kapteyn Astron. Institute), H. Heyer, H. Boffin (ESO), ESO
Explanation: When morning twilight came to the Paranal Observatory in Chile, astronomers Mark Neeser and Peter Barthel interrupted their search for faint quasars, billions of light-years away. And just for a moment, they used Very Large Telescopes at
the European Southern Observatory to appreciate the beauty of the nearby Universe. One result was |
|
