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Thread Statistics | Show CCP posts - 7 post(s) |
Vir Hellnamin
Gradient Electus Matari
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Posted - 2009.09.11 15:51:00 -
[31]
Thanks for the blog, was good read. Brought memories of panic about the clock-skew's in missions etc... :P
Btw, how does the Dread blob mega-bump relate in time-wise to this blog? I recall one vid where a Dread blob would just drop from warp (or from jump-in) and few would after a secs just go ballistic in random directions... -- "Entering MH means instant death. It's worse than 0.0. Even the asteroids shoot back." - Alex Harumichi [GRD]
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Rhys Onasi
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Posted - 2009.09.11 15:52:00 -
[32]
Originally by: CCP Fallout
Originally by: Michayel Lyon Bump.
Sorry, I couldn't resist...
You win this thread ;)
LOL!
I didn't even get that joke at first. Completely went over my head. Yes indeed, you win this thread.
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Lialem
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Posted - 2009.09.11 16:09:00 -
[33]
O M G,
Gingerdude deserves vacations CCP!!
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Kile Kitmoore
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Posted - 2009.09.11 16:20:00 -
[34]
At least you have collision detection, amazing how many MMO's don't. Thanks for the write up, very informative.
I noticed a number of mission maps where targeting something 8km away can't be done, or jettison a can and it sends 20km away even though there are no obstructions around you. I always assumed they were just bugs with the collision detection around certain objects or the object had a larger collision field then it really needed. So my question, is the later true or this is tied up to desyncing or both?
Thanks again for the great write up!
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Rakshasa Taisab
Caldari Sane Industries Inc. Ethereal Dawn
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Posted - 2009.09.11 16:21:00 -
[35]
Uh... Oh... Weird iteration of binary trees?... I assume it was iterating down _both_ children before itself.
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Steve Thomas
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Posted - 2009.09.11 16:26:00 -
[36]
Edited by: Steve Thomas on 11/09/2009 16:30:27 Edited by: Steve Thomas on 11/09/2009 16:26:24 So its now safe to hot drop 50 titans out of a cargo hold? Cool!
oh and desink is fixed!
(Im sorry but I now have a mental image of the sigh of relief as a cargo ship jetisons 50 titans
I hope they did not try it with a probe.
Originally by: Kile Kitmoore At least you have collision detection,
I always say if you need colision detection to let you know you just crashed into a space station and exploded you need to cut back on the recreational substances but thats just me being weird again.
*.* *.* *.* *.* *.* *.* *.* *.*
Stop freaking worrying about why things the developers did 5 years and more ago no longer make sense. |
Serni Vader
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Posted - 2009.09.11 16:27:00 -
[37]
This blog would actually make the bases behind a great CCP short video. CCP GingerDude is hard a work with the long, annoying, and tedious process of fixing the desync issue. After much hard work, he finally things he's got something that works and the evil QA pounces on him about a problem with it. After another long set of hard work, where CCP GingerDude is losing hair and is visibly increasing in age he finally finds a solution that without a doubt will work. After all those months of hard work on the issue he finally is able to leave the CCP building and see sunlight and other people for the first time. But just has he is about to enjoy the scene he gets a call on his phone. To his great surprise its QA telling him they have found a problem. CCP GingerDude then does the classic yelling into the air "NOOOOOO!", and the short ends. Great yea! |
Michayel Lyon
The Graduates Morsus Mihi
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Posted - 2009.09.11 16:28:00 -
[38]
Originally by: Rakshasa Taisab Uh... Oh... Weird iteration of binary trees?... I assume it was iterating down _both_ children before itself.
- Pre-order
- Post-order
- In-order
Which one to chose depends on the application. --- Lasiverin Dark > Is everyone here allied? Red Knight > we are allied by our zombie like ability to ***** missions
GM Xamother: "Beeing online is not considered harassment or exploit." |
LaVista Vista
Conservative Shenanigans Party
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Posted - 2009.09.11 16:33:00 -
[39]
Originally by: Redbad CCP GingerDude, you deserve to wear the golden "I killed lag!" T-shirt at the Fanfest! Sweet job and well done!
He didn't kill lag though.
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Melos Tellemey
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Posted - 2009.09.11 16:36:00 -
[40]
Edited by: Melos Tellemey on 11/09/2009 16:37:13 Great work Gingerdude. I cant believe how thoroughly you fixed it. and how dedicated you and the QA department were to utterly eradicate any instance of it. Hypothetical or not. :-)
You deserve a vacation.
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Daedalus II
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Posted - 2009.09.11 16:39:00 -
[41]
Quote: Remember that both client and server run the exact same code. When an object is added to space with the client already in the scene, both client and server start with every variable holding the same value. When logging into a scene which the server has already loaded, the server will have calculated a velocity value from the previous tick and store that as a temporary. When the client has no such temporary and incorrectly assumes that your current velocity is also your previous velocity and if a ball was in mid-collision during that very first tick, what happens? Desync.
A quick test where I added this extra information to the packets sent to the clients eliminated all desync cases completely and utterly.
I wonder if this fix has the added bonus of large ships not appearing to come out of warp sideways? As the client assumes that all ships that enter its grid the first time have a default angle (probably 0), large bulky ships tend to look as they come in sideways before the graphics engine slowly aim the ship in its actual moving direction. This is particularly obvious on freighters and Orcas coming out of cloak. But if this information is now sent by the server in the first packet, the client should know which direction the ship has right? or is it JUST the velocity and only the velocity that is sent?
Not that this is a big issue, it's just a bit annoying.
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Jason Edwards
Internet Tough Guy
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Posted - 2009.09.11 16:51:00 -
[42]
Quote: Clock skew is not desync When your shield and cap show wrong values, e.g. you start taking armor damage while still showing healthy shield status or the inverse when you don't take armor damage when you think your shield is gone, you're experiencing clock skew.
I always thought that it was Tactical shield manipulation that was bugging this one up. Never really got this one to work consistently enough to get it to work. Except the very first t3 sisi patch way back.
Quote: So, what is desync? It is the situation when the server and your client disagree on the position of an object in space at a given time.
Capship grinding I find is super easy at demonstrating this. I have also been able to fairly consistently do this with hg snaked out ares.
Quote: Every time a poor programmer-type of person such as myself starts to feel good about fixing stuff, evil, nasty, vicious QA-type people butt in. Testing the fix revealed that it was still sometimes possible to get desynced. All you had to do was to eject about 50 titans from your cargohold into space and then log or warp into that exact spot after a server reboot. Happens all the time on TQ...
because you know... that happens all the time.
Quote: Nice, so problem solved, right? Well, almost. At this time we wrote the patch notes for Apocrypha 1.5 and claimed to have fully fixed the issue. And we had, really. But I wasn't completely done.
So if I want to be lame and stationcamp in a moros or thanny. If I'm in docking range. I know forsure I'm in docking range? Grate success?
Quote: First, I took a long hard look at how we bump ships apart after the titan fix. Although grateful that it had revealed the desync issue, I had never been very satisfied with how the distribution of force to move the ships out of collision worked. It yielded too much speed for heavy objects and too little for lighter ships. After a few tweaks I settled for a much better approach: heavily intersecting ships were now bumping much less and titans could now simply push lighter ships out of their way. Titans where now losing only a small fraction of their speed when colliding with lighter ships, without the lighter ships shooting out like an air-filled balloon submerged in water being released.
HArd to bump the titan on purpose now? Even with a mwd bs?
Quote: Except evil, nasty, vicious QA, who were dead set on crushing my ego and abolishing happiness from the world at large. Again. Two days before Apocrypha 1.5 patch day, no less. How these guys manage to sleep at night, I do not know.
<3 QA
Quote: They'd figured out that they could get desync by going in a pod really close to a station, creating a bookmark there, and then warping a titan to that bookmark so that it intersected the station in many places. I had only a couple of hours to do something before the final build or else the patch would be delayed for weeks. Quickly employing the process of elimination, we determined that my bouncing tweaks or some other cleanup was somehow to blame and that the fix for the previous velocity issue was sound. Thus, all those extra bumping tweaks and the fix for the hypothetical desync scenario were quickly reverted, leaving only the core velocity issue fix in the patch.
As opposed to now? Where if you cyno the titan too close to any anchored thing... it goes flying 100km+ Personally I'm a pro at cynoing titans. Never a single bad bump. But I have seen the previous one. Ironically though there was pretty much no fear for the titan as a 200 man capfleet and about 800 subcap fleets were out and about. Who had nothing at all to shoot.
One question remains.
Would this also be desync? Warped off moms who arent quite warped off? ------------------------ To make a megathron from scratch, you must first invent the eve universe. ------------------------ Life sucks and then you get podded. |
Cagot
Spelunkers
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Posted - 2009.09.11 17:24:00 -
[43]
Kudos to you and the QA team. What an amazing job of debugging!
Woot!
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Huan CK
Gallente GK inc.
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Posted - 2009.09.11 17:25:00 -
[44]
I got a new favourite DevBlog!! Awesome :D I can literally feel your pain, as I've been in similar situations before :P
My videos: Watch on youtube. |
Nemtar Nataal
Demonic Retribution
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Posted - 2009.09.11 17:26:00 -
[45]
Nice write up
Good to see that you guyes are flaming for the development of EVE as much as the rest of us does in playing.
Sounding quait geeky here but a long night debugging session with some real result can really save your "day" (in this case properly morning)....keep going on the nice little tweeks...
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Rainhailer
Gallente Einherjar Rising Cry Havoc.
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Posted - 2009.09.11 17:31:00 -
[46]
Originally by: Blazde Ginger it's all cool that is fixed but I submitted a bugreport on the 3rd Feb about the out of order balls, weeks before the new collision mechanics were on Sisi at least. If you'd read it then you could have had a fix in Apocrypha or at the very least a quick workaround to prevent the most common desyncs.
And I'm still amazed you weren't able to reproduce it earlier (it was at least 2 years old) considering we were 'reproducing' it daily on TQ and it took me an afternoon to reproduce it reliably when I actually tried with just 3 clients and no titans in cargoholds hax. This was back in ~October 2008 but when I mentioned it in #eve-chaos I got told that a) devs couldn't discuss the desync bug (cos they might say something that differed from the party line and get quoted on later or something like that) and b) that in anycase other people had already submitted reproduction cases needing as little as one client and an asteroid belt (which I checked was indeed possible).
It's just not all that convincing that you tried hard to fix this before the CSM started insisting you take it seriously (and if that is the case they deserve some credit for it).
Regarding the remaining desync with titans warping into stations please check out the other part of my bugreport ( https://bugs.eve-online.com/mybugreports.asp?Action=View&ID=69209 ) about the tiny desyncs I got and suspected were due to floating point inaccuracies possibly from the client and server being compiled slightly differently. That's exactly the kind of scenario I'd expect the tiny desyncs to mushroom into real desyncs, especially if your math changes happened to exacerbate the problem.
Deal with it. They fixed it. Yay!
Easily my favorite Dev Blog ever.
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Khaelis
Caldari Daikoku Enterprises Inc.
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Posted - 2009.09.11 17:32:00 -
[47]
Interesting read!
Thanks for the writeup, I only wish we could get more detail filled juicy dev blogs more often.
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Nareg Maxence
Gallente
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Posted - 2009.09.11 17:41:00 -
[48]
One of the best devblogs I have read. And yes, you deserve a vacation.
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Melissa Brown
Marquie-X Corp
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Posted - 2009.09.11 17:53:00 -
[49]
Quote: Every time a poor programmer-type of person such as myself starts to feel good about fixing stuff, evil, nasty, vicious QA-type people butt in.
This made me smile and sad at the same time...
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Vala Draaken
Madhatters Inc. The Initiative.
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Posted - 2009.09.11 18:04:00 -
[50]
Outstanding detective work, excellent blog, and cheers for QA --------
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Pattern Clarc
Celtic Anarchy
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Posted - 2009.09.11 18:24:00 -
[51]
10/10 Would recommend ____ Minmatar Children of Sol
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Devan Corvel
The Golden Phoenix Inc.
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Posted - 2009.09.11 19:15:00 -
[52]
Kudos on a very entertaining explanation of the situation!
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Bartholomeus Crane
Gallente The Crane Family
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Posted - 2009.09.11 19:27:00 -
[53]
Having debugged concurrent programs myself, I know how difficult it can be to fix these types of heisenbugs. So well done and thanks for taking the trouble. -- Quis custodiet ipsos custodes? |
Serena Hennessy
Koshaku
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Posted - 2009.09.11 19:27:00 -
[54]
This fix will make a LOT of players very happy :)
Thanks for all the time and effort on this GingerDude, and great devblog :)
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Frug
Repo Industries
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Posted - 2009.09.11 19:51:00 -
[55]
Cool blog. CCP Gingerdude sounds like a pretty cool guy. - - - - - - - - - Do not use dotted lines - - - - - - If you think I'm awesome say BOOO BOOO!! - Ductoris Neat look what I found - Kreul Whisper/PrismX 4 emperor |
T'san Manaan
Minmatar
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Posted - 2009.09.11 19:57:00 -
[56]
I didn't understand any of the technical stuff, But I found it a very interesting read none the less.
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Stein Voorhees
Caldari Ghost in the Machine
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Posted - 2009.09.11 19:58:00 -
[57]
Ginger - you are Legend
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Vxrasa
Caldari Smegnet Incorporated Libertas Fidelitas
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Posted - 2009.09.11 20:03:00 -
[58]
CCP hire this man!
Oh wait...
Thx for no more Desync! \o/ ------------------------------------------------
-{Smegnet Incorporated Recruiter}- |
Gnulpie
Minmatar Miner Tech
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Posted - 2009.09.11 20:30:00 -
[59]
"The dev who killed desync!"
Good reading, not that I all understood, but still very good reading.
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Pliauga
Gallente
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Posted - 2009.09.11 20:34:00 -
[60]
Holy s**t, this blog is awesome (no sarcasm intended)
Can't wait for Dominion to hit singularity.
------- "Skynet" is my internet provider, should I be worried? |
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