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Re: Mutation events - slowness examples

From: Sean Hogan <shogun70@westnet.com.au>
Date: Thu, 25 Jun 2009 17:25:21 +1000
Message-ID: <4A432661.1040806@westnet.com.au>
To: Jonas Sicking <jonas@sicking.cc>
CC: François REMY <fremycompany_pub@yahoo.fr>, www-dom@w3.org, "Michael A. Puls II" <shadow2531@gmail.com>
Jonas Sicking wrote:
> On Wed, Jun 24, 2009 at 11:53 PM, Sean Hogan<shogun70@westnet.com.au> wrote:
>   
>> Jonas Sicking wrote:
>>     
>>> On Wed, Jun 24, 2009 at 8:52 PM, Sean Hogan<shogun70@westnet.com.au>
>>> wrote:
>>>
>>>       
>>>> I've made a couple of tests pages for DOMAttrModified (attached).
>>>>
>>>> test4.html modifies (1024 times) the title on an empty div and measures
>>>> execution time without / with DOMAttrModified listener.
>>>>
>>>> test5.html modifies (16 times) the title on a populated div.
>>>> Additionally, the contents of the div are styled based on the title. eg
>>>> div[title="After"] ul li {...}
>>>>
>>>> The repetition counts are chosen to get reasonable timing data.
>>>>
>>>> Results (approx)
>>>> test4:
>>>> Firefox: 25ms -> 120ms
>>>> Opera: 35ms -> 120ms
>>>>
>>>> test5:
>>>> Firefox: 43ms -> 48ms
>>>> Opera: 50ms -> 50ms
>>>>
>>>> Note: Safari doesn't trigger DOMAttrModified events.
>>>>
>>>> Conclusion (tentative):
>>>> The non-JS overhead of DOMAttrModified events is irrelevant to the UX,
>>>> being
>>>> well under 1ms per event.
>>>>         
>>> I'm not sure I follow, 25ms -> 120ms seems quite relevant.
>>>       
>> 95ms for 1024 events. That's less than 0.1ms per event, which is why I would
>> say irrelevant to user-experience.
>> How would you define "irrelevant to the user experience" and do you think
>> any alternative could do significantly better?
>>     
>
> I don't really have any data on how much attribute-setting performance
> sensitive applications are doing, or will be doing in 5 years. So
> while it's 0.1 ms per event, you have to multiply that by an unknown
> number of events.
>
> So to me it's the percentage-wise change that is interesting. Unless
> we have reason to believe that the whole operation happens rarely
> enough that performance in general just isn't an issue at all.
>   
That doesn't answer either question.
> / Jonas
>
>   
Received on Thursday, 25 June 2009 07:26:16 GMT

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