FreeBSD

最近 current 邮件列表讨论的很凶的一个问题是，MySQL很不理性地在每一个I/O操作时都调一次time()。这一操作在FreeBSD上面相当的昂贵(为了保证精度)，而Linux采取了许多优化(有些是牺牲精度的)措施，因而性能差距越来越大。

于是有一个人在FreeBSD上做了试验，说改一下默认的时钟能够将性能提高6倍……不带这么玩的，ft……

BTW. clive也测了一下，在他机器上结果是：

A collegue of mine has reported a FreeBSD “bug” that, when the main thread exits, the whole process is terminated. He complained that pthread_detach() would not cause the thread to run without the main thread, while Linux did.

With some experiments we have figured out that this is actually a Linux bug, which violates POSIX. Interestingly, Solaris has the same behavior that FreeBSD have.

The POSIX pthread_create() said:

Note that the thread in which main() was originally invokeddiffers from this. When it returns from main(), the effectshall be as if there was an implicit call to exit() usingthe return value of main() as the exit status."

I think we would be going to release 6.0-RC2 soon, to encourage more testing against the recently caught issues that addressed several race conditions, etc.

It seems that we still have some race conditions that can lead to strange issues and we may want to discourage this for 6.0-RELEASE.

Alan Cox has committed some fixes for the issue, hope these can be merged back.

Strange thing happen.

0. Start your FreeBSD single-user.
1. Run /etc/netstart so your network is up.
2. Run /etc/rc.d/sshd start so you have sshd
3. Use ssh to login localhost, then su(1) to root
4. Type “init q”

Then init(8) would crash with signal 11. Yes, it was killed. As soon as kernel found this, it would panic with “Going nowhere without my init!”.

Well, this Saturday and Sunday is not for rest, because we have a 7-days’ vacation from October 1.

I think FreeBSD 6.0-STABLE (RELENG_6) is in a quite nice shape and it’s a good time to cut 6.0-RC1 (also RELENG_6_0) and be more careful committing code against RELENG_6. However, according to my diff service there are still a lot of unmerged changes.

I have submitted a plenty (about 4 or 5 or even 6 dozens) of MFC requests last week. I wish that the diff reduction part of these changes, in conjunction with important bugfixes, would got approved soon so we will have a healthy RC1 for test.

Emily Boyd同学设计的新版 www.FreeBSD.org 今天上线了，很漂亮。不知道我们什么时候能让中文版跟上……

庆祝一下。

我另外架了一个简陋的RELENG_6和7-CURRENT代码对比的网站。希望这次RELEASE我们不要再遗漏什么重要的东西了。

关于 FreeBSD 的某处默认安全设置的问题，给security team发信，得到security-officer的一封关于对这个问题进行更深入阐释的质询，以及一封来自另一个committer的反驳意见。写信挑战了一把，看看结果吧。总体来讲我觉得权威错了，不过即使他对了，我想这次也能学到不少东西。

Today jianghong has pointed out that ConnectEx found in Windows Socket API has combined the connection and sending of the first block of data together within one system call. I think this is desirable for us too, as this can reduce unnecessary context switches.

FreeBSD has accept_filter(9) mechanism that does similiar thing for accept(2).