Author jcea
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Date 2011-12-12.15:13:11
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Message-id <1323702792.33.0.734335144949.issue13405@psf.upfronthosting.co.za>
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> - why an empty "dtrace" module?

This is preliminary. I am thinking about dynamic probes, something like "logging" module but using dtrace. Still experimenting, not sure is actually possible.

Martin V Löwis suggested to use "sys.flags".

Undecided yet.

> - I'm worried that you're adding lots of delicate code inside
> critical core functions. Perhaps most of it can be factored out in
> separate functions living in another (dtrace-specific) C file? I
> don't think we really want to maintain some asm("nop") in the GC
> module, and I'm not even talking about the madness in ceval.c.

ceval.c madness is greatly reduced in the last version. I was not happy with it either. I am open to suggestions...

The point of DTrace probes is its very low overhead. If I change macros to external function calls, your performance will be suffer.

That said, I am open to suggestions, more understandable code, etc.

> - instead of generating code data (line numbers etc.) up front, why
> not generate and cache it lazily? that way, it would only be
> generated when the probes are really used (IIUC)

This case is special. This data is used by the kernel, when a DTrace script does a "jstack()". At this moment you can not CALL anything. You don't even have loops or "if".

Example: your program seems hangup, aparently. You can write a single line DTrace script to dump the jstack and see what your program is doing, even if it stuck in, let say, a function call. At this moment you can't call ANYTHING. So I precalculate the line offsets at import time, and use the table here. There is little else I can do, in kernel context.

> For higher-level benchmarks, I suggest you take a look at
> http://hg.python.org/benchmarks/

Good suggestions. I will check it.
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Date User Action Args
2011-12-12 15:13:12jceasetrecipients: + jcea, loewis, rhettinger, ronaldoussoren, belopolsky, pitrou, wsanchez, movement, techtonik, serverhorror, glyph, laca, twleung, jbaker, robert.kern, sirg3, danchr, dhduvall, dmalcolm, mjw, Garen, neologix, lasizoillo, fche, hazmat, jmcp, scox
2011-12-12 15:13:12jceasetmessageid: <1323702792.33.0.734335144949.issue13405@psf.upfronthosting.co.za>
2011-12-12 15:13:11jcealinkissue13405 messages
2011-12-12 15:13:11jceacreate