Sounds like we are talking about different scripts. The only one I could
find was test/mjsunit/string-add.js ... which doesn't seem to do any timing
by itself, just doing assertion checks - and the assert functions are
defined in mjsunit.js which is why I'm getting an exception if I don't
execute it before string-add.js

Since I couldn't get any timing I added some myself in the main entry point,
but that obviously includes startup/shutdown. That's also why I noticed
shell calls V8::Dispose but d8 doesn't (at least not anywhere near the main
entrypoint).

I was trying to reproduce it on windows but I couldn't get any sensible
values, everything drowned in the noise of startup/shutdown and was pretty
much random. I could also test on several debian linux boxes, but it
probably only makes sense if I find the correct script to run. Sorry I
couldn't be of more help, I'm still trying to find my way around in the
project and sometimes make stupid mistakes.

2009/6/8 Anton Muhin <[email protected]>

> Good day, Tobias!
>
> On Sat, Jun 6, 2009 at 11:34 AM, Tobias Käs<[email protected]>
> wrote:
> > I noticed that shell does a V8::Dispose and d8 doesn't do this ... is
> > that included in your timing? Also, unless you are averaging multiple
> > runs, the total time is so small that it may be just some startup/
> > shutdown noise?
>
> I did more runs and the pattern is really stable: d8 shows almost
> identical times every time and shell shows this 1.5 slowdown most of
> time, but not always.
>
> May you elaborate a bit on V8::Dispose?  Timing is just as in
> string-add.js, so that doesn't include startup/shutdown stuff.
>
> >
> > PS: Are you using modified code or is this platform-specific
> > behaviour? I had to add mjsunit.js to the command line, otherwise I'm
> > getting an exception. Plus I don't get any timings out of d8/shell.
>
> Hmm, that was on Linux and ran just fine.  What's the platform you
> experienced problems on?
>
> Thanks a lot and yours,
> anton.
>
> >
> > On 5 Jun., 17:09, Anton Muhin <[email protected]> wrote:
> >> Dear v8ers,
> >>
> >> Erik pointed out that my r2110 dramatically reduced performance of
> >> several benchmarks, including string-add.  I compiled two versions,
> >> with and without 2110 and they ran fine on my box.  Erik suggested to
> >> run them on newt.aar and here began the mistery: unless I misbuilt the
> >> stuff results look:
> >>
> >> ant...@newt:/home/erikcorry/b$ ~/d8-2110 string-add.js && ~/d8-2111
> >> string-add.js
> >> Time (string-add): 301000 us.
> >> Time (string-add): 301428 us.
> >> ant...@newt:/home/erikcorry/b$ ~/d8-2110 string-add.js && ~/d8-2111
> >> string-add.js
> >> Time (string-add): 301857 us.
> >> Time (string-add): 302857 us.
> >> ant...@newt:/home/erikcorry/b$ ~/d8-2110 string-add.js && ~/d8-2111
> >> string-add.js
> >> Time (string-add): 309714 us.
> >> Time (string-add): 306142 us.
> >> ant...@newt:/home/erikcorry/b$ ~/d8-2110 string-add.js && ~/d8-2111
> >> string-add.js
> >> Time (string-add): 300714 us.
> >> Time (string-add): 301857 us.
> >> ant...@newt:/home/erikcorry/b$ ~/d8-2110 string-add.js && ~/d8-2111
> >> string-add.js
> >> Time (string-add): 301571 us.
> >> Time (string-add): 300714 us.
> >> ant...@newt:/home/erikcorry/b$ ~/d8-2110 string-add.js && ~/d8-2111
> >> string-add.js
> >> Time (string-add): 302571 us.
> >> Time (string-add): 301428 us.
> >> ant...@newt:/home/erikcorry/b$ ~/shell-2110 string-add.js &&
> >> ~/shell-2111 string-add.js
> >> Time (string-add): 446800 us.
> >> Time (string-add): 302142 us.
> >> ant...@newt:/home/erikcorry/b$ ~/shell-2110 string-add.js &&
> >> ~/shell-2111 string-add.js
> >> Time (string-add): 306857 us.
> >> Time (string-add): 309857 us.
> >> ant...@newt:/home/erikcorry/b$ ~/shell-2110 string-add.js &&
> >> ~/shell-2111 string-add.js
> >> Time (string-add): 449400 us.
> >> Time (string-add): 303285 us.
> >> ant...@newt:/home/erikcorry/b$ ~/shell-2110 string-add.js &&
> >> ~/shell-2111 string-add.js
> >> Time (string-add): 436800 us.
> >> Time (string-add): 306428 us.
> >> ant...@newt:/home/erikcorry/b$ ~/shell-2110 string-add.js &&
> >> ~/shell-2111 string-add.js
> >> Time (string-add): 432200 us.
> >> Time (string-add): 304000 us.
> >>
> >> (r2111 rolls 2110 back, d8 and shell are corresponding binaries, built
> >> as scons -j4 sample=shell and scons -j4 d8 correspondingly).
> >>
> >> Fun facts: d8 for both 2110 and 2111 runs in same time, shell for 2110
> >> usually runs 1.5 (!) longer, but sometimes (~10-20% of the cases)
> >> identically to 2111.
> >>
> >> Does anyone have any idea what might have happened?  Erik suggested
> >> that things are linked somewhat differently.
> >>
> >> Change itself looks quite plain and it's not obvious how that can
> >> introduce any regression:
> >>
> >> The only thing I can immediately see is expensive IsJSGlobalProxy, but
> >> why this is that instable, that'd be odd if more invocations to
> >> IsJSGlobalProxy would lead to more GCing.
> >>
> >> Any ideas are most appreciated.
> >>
> >> tia and yours,
> >> anton.
> >
>

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