Paul E. McKenney
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Paul E. McKenney
paulmckrcu
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Paul E. McKenney
paulmckrcu
@ljs @brauner @cyphar LaTeX is not perfect, and it has a learning curve, but it is quite capable. Especially if you cheat like I do and so some of the work in other scripting languages.
As to the LaTeX build times, I suspect that they are much more tolerable when your book is less than 700 pages. ;-)
As to the LaTeX build times, I suspect that they are much more tolerable when your book is less than 700 pages. ;-)
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Paul E. McKenney
paulmckrcu
@brauner @cyphar The original nroff and troff from which groff descends had to do typesetting (and in troff's case, phtoto-typesetting) on systems having a 64Kbyte address space. So Moses simply did not have sufficient space to record nroff and troff as sins on his tablets. Plus there is not a huge number of people who, like me, are older than nroff and troff, but I am here to tell you that both nroff and troff seemed pretty nice to me back in the day.
So who knows? It just might be time for a change in format. After all, I long ago made the switch from nroff/troff to LaTeX. ;-)
So who knows? It just might be time for a change in format. After all, I long ago made the switch from nroff/troff to LaTeX. ;-)
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Paul E. McKenney
paulmckrcu
@jwseigh This stuff is tricky, and thank you for introducing me to the memory-to-memory single-instruction copy trick for Hazard Pointers.
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Paul E. McKenney
paulmckrcu
@jwseigh As always, much depends on your exact implementation. But what if the RSEQ reader picked up the pointer, took an unrelated long-running interrupt, took (and responded to) the membarrier IPI, then took another unrelated long-running interrupt? I do not believe that this would cause RSEQ to retry (though I might be missing something).
In that scenario, how is the updater to know that it should avoid reclaiming the object whose pointer the RSEQ reader will eventually store into its hazard pointer?
(I get the blog post: If you can uninterruptibly load and store the pointer, then membarrier() will either force the reader to see the new pointer or force the updater to see the updated hazard pointer.
I do not understand how your RSEQ trick works. Not yet, anyway.)
In that scenario, how is the updater to know that it should avoid reclaiming the object whose pointer the RSEQ reader will eventually store into its hazard pointer?
(I get the blog post: If you can uninterruptibly load and store the pointer, then membarrier() will either force the reader to see the new pointer or force the updater to see the updated hazard pointer.
I do not understand how your RSEQ trick works. Not yet, anyway.)
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Paul E. McKenney
paulmckrcu
@jwseigh If the vCPU preemption also blocks the guest-OS-level membarrier() call, perhaps you are OK?
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Paul E. McKenney
paulmckrcu
@jwseigh Hmmm, interesting... Does RSEQ now fail in response to vCPU preemption?
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Paul E. McKenney
paulmckrcu
@jwseigh I thought that membarrier only guaranteed ordering, but perhaps you have a trick that I missed.
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Paul E. McKenney
paulmckrcu
@jwseigh Nice! But if I may ask, how does this deal with the possibility that a updater on some other thread concurrently changed the pointer that you are trying to protect?
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Paul E. McKenney
paulmckrcu
Today I learned that gawk has a "--debug" command-line argument, and has had for more than ten years. In my defense, I using awk for about 30 years prior to that...
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Paul E. McKenney
paulmckrcu
@Louson Never forget: It is easier to circle the square than to square the circle.
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Paul E. McKenney
paulmckrcu
@jwseigh Rightly or wrongly, this site says tau is 2π. https://en.wikipedia.org/wiki/Tau_(mathematics)
Me, I glanced too quickly at the first occurrence of 𝜏 (tau) in this thread and mistook it for the Roman-alphabet letter "r". ;-)
Me, I glanced too quickly at the first occurrence of 𝜏 (tau) in this thread and mistook it for the Roman-alphabet letter "r". ;-)
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Paul E. McKenney
paulmckrcu
@tommythorn Indeed, 2π day and 𝜏 day are one and the same! But I suspect that more people would prefer to eat two pies than would prefer to eat a tau. ;-)
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Paul E. McKenney
paulmckrcu
@morgan I would attempt a witty response, but I would probably end up sounding like a square. ;-)
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Paul E. McKenney
paulmckrcu
@brauner Fair enough! But I might nor might not remember that you forgot. ;-)
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Paul E. McKenney
paulmckrcu
@brauner RCU uses many mutexes so that RCU users don't have to? ;-)
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Paul E. McKenney
paulmckrcu
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Paul E. McKenney
paulmckrcu
@ljs It is amazing how destructive unanticipated use cases can be. Destructive, but necessary...
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