통근할 때 만나는 유쾌한 사람들

가을의 아침. 춥기는 춥지만 추우냐고 하면 그 정도까지는 아니다.

언제나 같은 시간에 같은 거리를 통근하고 있으면 자주 만나는 사람이 있다는 것이 알아진다.  오늘은 그중의 특징적인 사람을 소개하겠다.

■냅색 아줌마 고친 이름: 카리아게(뒤머리를 쳐올려 깎아 있는) 아줌마

  • 조우율: 20%
  • 특징: 뒤머리를 쳐올려 깎아 있다.  나와 같은 차량에 탄다.  검은 냅색을 짊어지고 있다.

■헤드 폰 형님

  • 조우율: 20%
  • 특징: 머리에 헤드 폰을 붙이고 음악을 들면서 걷고 있다.  머리와 헤드 폰의 일체감이 굉장하다.

■ ZZTop

  • 조우율: 20%
  • 특징: 언제나 편의방 앞에서 서 있다. 수염과 체형이 왕년의 록 기타리스트와 비슷한다.

 

이렇게 생각하면 매일의 통근도 또 재미있지요.

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xmxとxmsは小さければ小さいほど良い?

かなり誤解していたところがあるが、JVMのヒープ領域は大きければ大きいほど良いわけではないようだ。逆に小さければ小さいほど良いらしい。

http://people.apache.org/~markt/presentations/2009-04-01-TomcatTuning.pdfには以下の記述がある。大きいとGCの処理に余分に時間がかかってしまうことが原因のようだ。偉い人が書いて、apache.orgに掲載されているんだから間違いないだろう。

-Xms/-Xmx
  – Aim to set as low as possible
  – Setting too high can cause wasted memory and long GC cycles

また、http://www.coderanch.com/t/504688/java/java/Mamimum-Value-which-allowed-XMXによると、SUN JVM以外の商用JVMでは取れるだけ大きくとると恩恵を得られるとのこと。うーん、経験則に基づくものとはいえ、すばらしい情報だ。

I don’t really have a simple answer for you, but here are some things to keep in mind…

1. Never use swap for the JVM…. I repeat. NEVER use swap for the JVM. The garbage collector is the worst case scenario for swap. It touches all memory, and specifically targets the least recently used memory. The garbage collector will take hundreds, perhaps thousands, times longer to do it’s job.

2. Don’t go over 4 gb of heap for the Sun JVM. I have actually seen it as high as 9 gb, but that had dozens of gc related -XX flags, tuning it for the exact application. And even then, it would sometimes fall over during the day. The garbage collector just doesn’t behave very well at high heap sizes.

3. You can have higher heap sizes if you use the JVMs with better GC implementations — such as the newer JRockit, IBM version (whose name escapes me), the new Sun JVM (which I don’t think is out yet). These JVMs could probably give you better performance, and hence, bigger heap sizes. And of course, if you use the Azul JVM (with its pauseless GC), you can have a heap a big as you have the memory for.

As for sizing…

4. In general, the JVM will size the stack memory area to be about 1/4 the size of heap. This means, with a 4GB heap, you will need an additional 1GB for the stack area, and whatever memory needed for the JVM itself. With some JVMs, it is possible to size the stack space too.

Personally, I think it is best (if you want to use all the memory), is to simply try it, using this as an estimate. If it works, great. If it doesn’t, try a smaller heap size.

また、http://www.oracle.com/technetwork/jp/ondemand/application-grid/wls11g-pt-201107-otn-sc-439533-ja.pdfによると、xmxとxmsの値は、Long Lived Objectsのサイズの3倍程度に設定することがベストプラクティスだそうだ。

バドミントンメモ

サーブ以外は、ネットの上部の白いところに当てる気持ちで鋭い玉を返すイメージでやったら非常に感触が良かった。

もしかしたら、サーブもこれぐらいの気持ちのほうが良いのかもしれない。

올해 2번째 골절.. 그래도 괜찮아

어두워졌다. 좀 춥다. 겨울의 입구.

지난주 한 풋살에서 사람과 부딪쳐서 가슴을 다쳤다. 어쩐지 뼈에 금이 간 것 같다. 올해 두번째 골절이라니… 다행하게도 정도는 가벼운 것 같다. 하지만 내일에 풋살 시합은 캔슬해서 연회만 참석할 것이다.

다침 편력:
2005 무릎에 물이 괸다
2006 늑골 균열 골절
2007 창자(腸脛) 정강이 인대염
2008 늑골 균열 골절
2010 경추 헤르니아
2011늑골 균열 골절, 무릎에 물이 괸다, 늑골 균열 골절(2번째) <- 지금 여기

Mystery of morning assembly has been solved

It is dark. Comfortable weather.

Today, a mystery has been solved.

My company holds a brief morning assembly every day. The MC is always the same person from the sales department. Since I entered this company in July, I didn’t catch what he says at the beginning of the meeting because he speaks so fast and unclear.

I talked one of my colleagues about this “mystery”, and he also said that he didn’t understand either. I tried to decode his words with full concentration every morning. To my ear, he seemed to be saying “来襲用意の連絡事項のある方?”(meaningless sentence)

But today, my colleague said to me after the meeting that he could finally understand what the MC had said. He seemed to be saying “来社および連絡事項のある方?”, which is understandable in terms of conversational flow. I thought it was the right answer and was relieved.