TUturrini·Sep 27, 2019Submission
Fluxcapacitor – Run programs without blocking on timeouts
3 points · Open discussionmajek
fluxcapacitor
C2013–2019
majek / fluxcapacitor
fluxcapacitor
The engine that powers DeLorean!
6Distinct people
8Mentions
0Explicit recommenders
837GitHub stars
What to know before exploring
What it is
The engine that powers DeLorean!
GitHub
Where it is used
No documented product use has been verified yet.
What people are saying
No recommendation phrase was found in the indexed comments.
No classified warning is attached to this page. Read the discussions before treating silence as approval.
Also in these discussions
No other repository is repeatedly linked in the same discussions.
This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year8 dated mentions
Observed mentions: 2013-02-20 22:05:06 UTC to 2019-09-27 13:30:58 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2013 | 2013-01-01 00:00:00 UTC | 2014-01-01 00:00:00 UTC | 2 | 1 | 1 |
| 2014 | 2014-01-01 00:00:00 UTC | 2015-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2015 | 2015-01-01 00:00:00 UTC | 2016-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2016 | 2016-01-01 00:00:00 UTC | 2017-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2017 | 2017-01-01 00:00:00 UTC | 2018-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 2 | 0 | 2 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 1 | 1 | 0 |
What Hacker News says
8 sourcesYour snark aside, clocks are not perfect, and a malfunctioning clock might speed up or slow down.
Also, speeding up the clock is a technique already used in testing enviroments [1].
[1]: https://github.com/majek/fluxcapacitor
In Two Objects Not Namespaced by the Linux Kernel (2017)Doesn't 0.05s still seem like quite a long runtime for something like this? I wonder what it is doing under the hood that takes so long.
For start, it seems like they hijack a bunch of clock calls with LD_PRELOAD and then redirect vdso ones to syscalls just so they can interpose with ptrace. Why not do the manipulation in the PRELOAD?
I guess using the debugger API makes it easier to coordinate a bunch of processes, but you could probably do the same thing with some sort of IPC mechanism between PRELOADED targets. In the common case (single program running under FC, no IPC is needed.
It's unclear to me why they force any sleep duration at all, e.g., 10ms: https://github.com/majek/fluxcapacitor/blob/master/src/main....
It seems like there is room to optimize here, if one were really inspired :-).
In How to sleep a million years (2013)There's also fluxcapacitor:
https://github.com/majek/fluxcapacitor
In Show HN: TARDIS – Warp a process's perspective of time by hooking syscallsNice idea. Shameless plug: this reminds me a ptrace hack I did a couple years back:
fluxcapacitor
https://github.com/majek/fluxcapacitor#fluxcapacitor
https://idea.popcount.org/2013-07-19-how-to-sleep-a-million-...
In Maybe: run a command, see what it does to your files without actually doing itWith fluxcapacitor it will run in fraction of a second!
https://github.com/majek/fluxcapacitor#basic-examples
$ ./fluxcapacitor examples/sleep_sort.sh 1 4 20 3 55
In Sleep sort (2011)You can use `libfaketime` to test your software:
* https://github.com/wolfcw/libfaketime
Shameless plug: my project `fluxcapacitor` may also be useful for testing:
* https://github.com/majek/fluxcapacitor
In Year 2038 problemFluxcapacitor: spoof Posix time functions
58 points · Open discussion