[ Home | Articles | Account | People | Projects | FAQ ] Name: Pete Zaitcev
Member since: 2000-02-23 20:59:15
Last Login: 2008-05-17 19:36:24
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Rio and Upstart
Seen at Rio's place:
Fedora9のupstart、すごいんですけど...。さすがに組み込みみたいな速さでは無いけれど、これならサスペンドしなくても良いんじゃ...。
Which, in my very approximate translation means:
Upstart of Fedora 9 is great, mostly. As expected it includes no visible speed, so not using suspend is not good.
So, I guess that Rio expected improvements which would allow to stop suspending and they did not materialize... Which makes sense, but why the superlatives then? The title of the post was "upstartすげい！" with the exclamation mark. I would understand if he wrote that Upstart allowed him to end suspends, but no, "速さでない" is simple enough even for me to understand. Oh well, perils of international blogging.
Once I figured out that the control file syntax is documented in events(5) of all places, Upstart became rather tolerable, even welcome. I think that our famously poor bootstrap times (which are not that bad in Fedora when compared to other distros — I've seen real hard benchmarks — but are just bad for me as a user) have more to do with trying to execute too much crap. Upstart allows us to do it more efficiently, but it's a palliative.
UPDATE: piyokun comments that the right translation is more like "Of course it's not as fast as embedded (linux), but with (upstart) you can get by without suspending." So, the "shinakute" is like "doing", "mo" is change of state (he suspended before, but not anymore), "n" is explanation tag, and "ja" is uncertainty. Casual, of course. Oh, and "kumikomu" is a verb meaning "to incorporate". I had no idea that they had a native word for "embedded", instead of a katakanized borrowed word.
Syndicated 2008-05-14 07:35:27 (Updated 2008-05-14 17:48:31) from Pete Zaitcev
13 May 2008 (updated 14 May 2008 at 03:10 UTC) »
John Carmack and Linux VT
Our flight computer now has a display screen to show the current status to a pilot. My first inclination was just to mmap the framebuffer and pretend I was back in the days of DOS, but I decided to try and be a good linux programmer and use ncurses. It took me longer than I expected to get it working properly for displaying on the VGA for an application launched from a telnet session, and the performance was very bad. I wound up writing directly to the terminal device myself, spitting out all the escape sequences manually, but it was still quite appallingly slow. I have it working acceptably by only updating the various display items in a scanning fashion to avoid slowing it down on any individual frame, but I should have just followed my first thought and gone with a direct memory mapping.
I'm a little disturbed by the above, because I consider his application essentially equivalent to what Hercules does, and I never saw any performance issues with it. We all know that ncurses is a pig, and of course he should be using Slang instead of ncurses, but since he says that the result was slow even for the raw sequences, certainly this is not the issue. Weird.
It would be awesome if he posted his code somewhere.
UPDATE: John replies in comments:
The flight computer is only a 486-100, so it doesn't take much to bog it down, even with just text writes. I am doing straightforward fwrites and fprintfs to the console tty for everything.
It is at an acceptable rate now, so I probably won't make any other changes, but if RRL decides that they want anything fancy, like scrolling bar graphs, I will go straight to the framebuffer.
Syndicated 2008-05-13 01:25:22 (Updated 2008-05-13 20:14:59) from Pete Zaitcev
BadName is essentially conquered
The issue with random applications failing to start (Firefox, Nautilus) or blowing up (panel, gvim) with BadName took me about 3 months to find (the bug was filed at the end of January). I'm not sure if my fix is any good, need to poke Ajax about it.
So... Wasted a lot of time, learned several mildly interesting things about the code and people involved.
The sad part is how much it takes to start moving around any modern codebase, and that's with the same language and toolchain. I remember times when no part of the system was off-limits, but these days... not so much. If anything breaks in OpenOffice, I'm not even going to try fixing it.
Syndicated 2008-05-02 10:23:00 (Updated 2008-05-02 10:24:01) from Pete Zaitcev
23 Apr 2008 (updated 23 Apr 2008 at 21:15 UTC) »
Ted Tytso on [Open]Solaris
Ted suddenly decided to talk OpenSolaris. Pretty interesting... at least for me, since I spent 7 best years of my life in Sun's orbit.
In passing, aside from the bulk of the post, it seems to me that the final argument, about competitors selling Solaris support, does not hold water. This is exactly what Oracle attempted with their clone of CentOS and they weren't very successful, despite having a strong Linux team under Wim.
Other than that, he's probably right. But he's going to get responses. Whenever I mention Solaris (last time it was when I linked to Jeff Bonwick's blog), I get the most inane responses from Solaris fanboys. It looks like a very vocal community of users, if not contributors. Sounds like Apple almost.
This puts the damper on any dreams I may have about re-living the glory of my youth by getting back to hacking on that codebase.
UPDATE: Not sure why Levon decided to post his reply to his personal blog instead the one at Sun. Surely the other one is more relevant?
Syndicated 2008-04-23 18:12:46 (Updated 2008-04-23 20:38:59) from Pete Zaitcev
Random dmesg errors
I always was against kernel spewing user-generated errors into dmesg, like this:
npviewer.bin[4393]: segfault at f6712030 ip 67e7a0 sp ff9c39ec error 4 in libpthread-2.8.so[677000+15000]
Not helpful, not interesting.
However, the other day my desktop keeled over in a strange way... The /var/log/messages contained this (followed by a stack trace):
Apr 13 18:19:14 niphredil kernel: Xorg: page allocation failure. order:3, mode:0x4020
It looks like a bug in SLUB (does not seem registering with anyone who has the power to track it down though). But my point is, without the printout I would need to find what was happening by other means, and that would probably take forever.
Hmm... My world is shaken.
P.S. kgdb was merged into 2.6.26. The sky is falling.
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