Charles,
it's hard to comment this profoundly without giving it some serious and
time-consuming debugging first. Anyway, I assume that your problem
persists with both "offsets" and "start-at dates" even when
LD_PRELOADing libfaketime directly, i.e., without the "faketime" wrapper.
In this case, the observed behavior is quite typical for applications
which load system libraries (including time-related functions)
themselves at run-time. It basically means that the LD_PRELOAD mechanism
is somewhat bypassed by the application, which loads the real (not the
faking) library again after the linker has loaded the faking library.
Strange things (such as slow reactions with few-seconds-offsets or
endless hangs with larger offsets) occur when the application is
multi-threaded and one thread sees a faked time while another one uses
the real system time, and both try to synchronize.
If that's the case with iceweasel (idk for sure atm), there's nothing
libfaketime can do because that's a limitation of the LD_PRELOAD
mechanism. This is what makes faketime unusable with a few complex
runtime environments, such as the Sun Java JDK/JRE, and there currently
are no stable solutions known except for making the application
explicitly libfaketime-aware. That said, unless we figure out that this
is a libfaketime-internal bug and not a LD_PRELOAD limitation, there's
little hope that it can be changed anytime soon. I'd actually be very
happy about any suggestions on what to change about libfaketime to make
it work with such applications.
Charles Evans <mailto:charlesev...@chartertn.net>
5. August 2014 19:08
On Sun, 13 Jul 2014 20:21:00 -0400
<snip>
(I answered this many days ago, but it seems to have vanished.
possibly not the only email I sent to do so.)
The problem is with offset timing:
faketime -m -f "-1s" iceweasel
sets the clock to appear to run 1s behind.
the -f "+1s" and -f "-1s" cause problems.
BTW I updated to the backport Version: 0.9.6-1~bpo70+1
and it still has many of the same problems:
"-1s" pegs 2 cores at 100% forever.
"+1s" makes large menus that scroll do so extremely slowly.
