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Brad Fitzpatrick

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bug hunting [Jun. 27th, 2003|11:51 am]
Brad Fitzpatrick
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Never before have I spent so much damn time hunting for a bug. Blah. Anybody bored and want to audit memcached? (in wcmtools, see http://cvs.livejournal.org/) Somehow slabs_allocs is returning an object that's still in use, do either the slabs system is screwed (but it's so simple!) or somebody's holding a pointer too long. avva and I have been going at this for days, littering the source with asserts.

I even captured 30MB of traffic from server up to assertion error and wrote a playback program, parsing the tcpdump file, but it didn't cause a local crash.

In good news, going camping later today, and I'm almost fully up-to-speed on my fingerworks.com keyboard. I still fuck up sometimes, but it's not depressing anymore. For a few days there I was literally depressed... felt like a freshly crippled person (I'd imagine) or kinda like when I was Germany trying to talk to people at parties and getting frustrated that I couldn't express myself fast enough. Thing is, now real keyboards feel very weird.

blah. back to bug huntin'.
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Comments:
[User Picture]From: gorgonous
2003-06-27 12:09 pm (UTC)
How do you find the home row on a keyboard that's completely flat? Does it come with nubs on the F/J 'keys' like a normal keyboard?
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[User Picture]From: brad
2003-06-27 12:18 pm (UTC)
It has little bumpies on asdf and jkl; but really, I just put my wrists on the pads and go from there...
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[User Picture]From: sze
2003-06-27 12:37 pm (UTC)
damn. i want that touchstream LP keyboard. are you more productive on it or is it one of those things that's counterproductive? i hate the mouse so that keyboard's appealing...

oh and hi. sorry to budge in unannounced. i'm just a lurker. :)

hope you find said bug and squash it soon.
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[User Picture]From: brad
2003-06-27 01:13 pm (UTC)
Programming is damn nice on it. Gestures for so many useful commands and key combos.
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[User Picture]From: ccupguy
2003-06-27 12:41 pm (UTC)

eum...

I admit I don't understand a lot about that code where you put the asserts, but it strikes me funny that you're working with unsigned integers as pointers in there. Are those big enough to contain (define) all the necessary pointers you're bound to need in the live system?
I don't know if this is a relevant question at all, but I thought it can't hurt to ask :)
ccup.
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[User Picture]From: brad
2003-06-27 01:14 pm (UTC)

eum...

hm, we don't use unsigned ints as pointers....

in any case, we just got a great lead, so i think we're almost there.
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[User Picture]From: calliste
2003-06-27 12:52 pm (UTC)
Well the cool thing is that, in case of an emergency, you can still go back to English when in Germany. BTW, I keep bumping into Brian from LA all the time. Very funny. He now works at the Groove Station as a bartender and his German is fucking awesome. But that was just a random sidenote.
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[User Picture]From: brad
2003-06-27 01:07 pm (UTC)
:-(

Depressing. If I'd stayed, mine might be awesome. He had the advantage of a girlfriend who hardly spoke English.
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[User Picture]From: calliste
2003-06-27 04:56 pm (UTC)
Ohhhhhh, I didn't want to depress you even more with that. I have the feeling I gotta learn something called Taktgefühl at some point, or at least improve my skills thereof. Whatever. He's been living here ever since last ... err ... when were you here? April? Or even before that, and has been speaking German ever since. So there. Your German would be perfect in a situation like that. :P
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[User Picture]From: taral
2003-06-27 01:21 pm (UTC)
1. Slabs for objects of size 1 aren't very useful. I suggest bounding objects to a minimum size of sizeof(long).

2. If you do that, you can use the free objects themselves for the freelist, saving yourself some work. :)

Still looking for bugs...
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[User Picture]From: taral
2003-06-27 01:33 pm (UTC)
Can I suggest adding tracing? It might prove enlightening.

Is memcached multi-threaded?
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[User Picture]From: mart
2003-06-27 03:07 pm (UTC)

The keyboard thing is going to suck whenever you need to use someone else's PC! ;)

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