Improving interpreter startup speed

[Steve Holden]

BJörn Lindqvist wrote:
> 2008/10/27 James Mills <prologic at shortcircuit.net.au>:
>> On Mon, Oct 27, 2008 at 5:40 PM, David Cournapeau <cournape at gmail.com> wrote:
>>> Depends on the tool: build tool and source control tools are example
>>> it matters (specially when you start interfaciing them with IDE or
>>> editors). Having fast command line tools is an important feature of
>>> UNIX, and if you want to insert a python-based tool in a given
>>> pipeline, it can hurt it the pipeline is regularly updated.
>> Fair enough. But still:
>> 0.5s old startup is fast enough
>> 0.08s warm startup is fast enough.
>>
>> Often "fast enough" is "fast enough"
> 
> Nope, when it comes to start up speed the only thing that is fast
> enough is "instantly." :) For example, if I write a GUI text editor in
> Python, the total cold start up time might be 1500 ms on a cold
> system. 750 ms for the interpreter and 750 ms for the app itself.
> However, if I also have other processes competing for IO, torrent
> downloads or compilations for example, the start up time grows
> proportional to the disk load. For example, if there is 50% constant
> disk load, my app will start in 1.5 / (1 - 0.5) = 3 seconds (in the
> best case, assuming IO access is allocated as efficiently as possible
> when the number of processes grows, which it isn't). If the load is
> 75%, the start time becomes 1.5 / (1 - 0.75) = 6 seconds.
> 
> Now if the Python interpreters start up time was 200 ms, by apps start
> up time with 75% disk load becomes (0.2 + 0.75) / (1 - 0.75) = 3.8
> seconds which is significantly better.
> 
> 
But still not fast enough to be regarded as even close to "instant", so
you appear to be fiddling while Rome burns ...

reqards
 Steve
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Steve Holden        +1 571 484 6266   +1 800 494 3119
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