How to reset an Interpreter?
in [TCL]
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From: Arnold Snarb on 3 May 2010 19:22 Matthias Meier wrote: > Alexandre Ferrieux asked: >> But may I ask what you're trying to do ? > > I have an tcl-interpreter in a long running (c-written) server-process. > During server livetime various scripts [...] are interpreted > and i want to ensure that the scripts are don't affect each other. [...] > > Therefore i would like to evaluate each script in a 'new'/clean interpreter. > > But creating a new interpreter ( Tcl_CreateInterp() ) every time > would consume too much time. Have you tried it? Have you measured it? Is it *actually* too slow, or does it just seem like the kind of thing that *you think* maybe might be too slow? > Because the problem is time-critical im looking for the most > performant way to 'reset' the interpreter. > (I hoped there is a more performant way to do it then unsetting > the vars one by one) The fastest way I know of to get a new/clean interpreter is to create a new one. I'd try that first. If that turns out to be too slow -- actually and truly for real too slow -- then measure it, time it, and ask here again. (There are a few tricks you can use to speed interp creation up). But in any case, creating a new interp is most likely going to be faster (and for certain going to be more reliable) than trying to clean up an old one. --arnie
From: Alexandre Ferrieux on 4 May 2010 02:48 On May 3, 8:51 am, Matthias Meier <Me...(a)FuH-E.de> wrote: > Alexandre Ferrieux schrieb: > > > On Apr 29, 11:39 am, Matthias Meier <Me...(a)FuH-E.de> wrote: > >> Hello, > > >> i want to "reset" an Interpreter after evaluating a script to the state it was after initialisation. > >> (that means: delete all the vars/procs which were created during the script-evaluation) > > > But may I ask what you're trying to do ? > > I have an tcl-interpreter in a long running (c-written) server-process. > During server livetime various scripts (which have nothing to do with each other) are interpreted and i want to > ensure that the scripts are don't affect each other. > (i.E. just because one script uses variables (variable names) which an other Script uses too) > Therefore i would like to evaluate each script in a 'new'/clean interpreter. > But creating a new interpreter ( Tcl_CreateInterp() ) every time would consume too much time. > > Because the problem is time-critical im looking for the most performant way to 'reset' the interpreter. > (I hoped there is a more performant way to do it then unsetting the vars one by one) Note that the complexity/thoroughness of the solution depends on the level of cooperation to be expected from the scripts: - If you assume nothing (like 'they might even be viruses'), then the only sure-fire is to nuke and recreate (I'd even respawn a process to be on the safe side; yes I know you will label this as Too Slow). - If reasonable cooperation is thinkable, then just [namespace eval] them, and delete the namespace afterwards. Or even just [eval] them from within a proc, and fall out of the proc afterwards. In both cases, unqualified vars will *not* be globals, and will be removed wholesale. Of course the "cooperation" means for the script to never use [global] nor any explicit namespace. - for procs I'm afraid there's no other way than the enumeration I suggested, but it may be okay if your scripts are small enough to be so exquisitely fast (otherwise, the sheer time to load tens of procs would be too much anyway) -Alex
From: Matthias Meier on 5 May 2010 04:12
Arnold Snarb schrieb: > Matthias Meier wrote: >> Alexandre Ferrieux asked: >>> But may I ask what you're trying to do ? >> I have an tcl-interpreter in a long running (c-written) server-process. >> During server livetime various scripts [...] are interpreted >> and i want to ensure that the scripts are don't affect each other. [...] >> >> Therefore i would like to evaluate each script in a 'new'/clean interpreter. >> >> But creating a new interpreter ( Tcl_CreateInterp() ) every time >> would consume too much time. > > > Have you tried it? Have you measured it? Tcl_CreateInterp() = 0,065s Tcl_DeleteInterp() = 0,045s ==> 0,11s (On a Quad-Core 3.20GHz Intel-Xeon) > > Is it *actually* too slow, or does it just seem like the > kind of thing that *you think* maybe might be too slow? It *is* too slow because users waiting for respose while 10 to 50 scripts are evaluated. That would take 1 to 5 seconds just for creating and destroying the interpreter. Thanks, Matthias > > >> Because the problem is time-critical im looking for the most >> performant way to 'reset' the interpreter. >> (I hoped there is a more performant way to do it then unsetting >> the vars one by one) > > The fastest way I know of to get a new/clean interpreter > is to create a new one. > > I'd try that first. > > If that turns out to be too slow -- actually and truly for real > too slow -- then measure it, time it, and ask here again. > (There are a few tricks you can use to speed interp creation up). > > But in any case, creating a new interp is most likely > going to be faster (and for certain going to be more reliable) > than trying to clean up an old one. > > > --arnie |