On Fri, Sep 14, 2012 at 4:13 AM, Adam Barth <aba...@webkit.org> wrote:
> In connection with the thread on webkitPostMessage, I took a look at > what sorts of metrics we have currently for depreciated features. We > have high quality data for two groups of APIs: > > For mutation events, we measure what percent of Documents have > listeners for various kinds of mutation events: > > DOMAPI.PerDocumentMutationEventUsage.DOMCharacterDataModified: 2.85% > of all Documents > DOMAPI.PerDocumentMutationEventUsage.DOMNodeInserted: 4.78% of all > Documents > DOMAPI.PerDocumentMutationEventUsage.DOMNodeInsertedIntoDocument: > 0.21% of all Documents > DOMAPI.PerDocumentMutationEventUsage.DOMNodeRemoved: 0.07% of all Documents > DOMAPI.PerDocumentMutationEventUsage.DOMNodeRemovedFromDocument: > 0.0003% of all Documents > DOMAPI.PerDocumentMutationEventUsage.DOMSubtreeModified: 2.30% of all > Documents > > From this data, it's tempting to remove support for DOMNodeRemoved and > DOMNodeRemovedFromDocument as those are used extremely rarely. We > don't have any data for how much of this usage is attributable to > extensions. It will be interesting to watch this data as we > evangelize MutationObservers, especially among extension developers. > Is there an absolute number for those 0.07%? How is it calculated? Like Web Inspector has been using DOMNodeRemoved for its viewport-based text editor until very recently, so your 0.07% is likely to include millions of users. Is that expected? I wonder what will the drop be with the next major Chrome release. > Another metric we have is for Blob.webkitSlice: > > Ratio of Blob.webkitSlice calls to Blob.slice: 14.87% > Ratio of Blob.webkitSlice calls to Document creation: 0.0053% > > It's difficult to know how to interpret this data because we don't > actually correlate calls to webkitSlice with Documents or Pages. > Instead, we just count the total number of calls across all Documents. > This gives us an upper bound on how many Documents (or Pages) would > be affected by deleting Blob.webkitSlice, but doesn't measure that > information as accurately as the data we have for mutation events. > > We are also gathering metrics on the usage of vendor prefixes in CSS > properties, but that histogram doesn't appear to have been in the > field long enough to have meaningful data. > > Adam > _______________________________________________ > webkit-dev mailing list > webkit-dev@lists.webkit.org > http://lists.webkit.org/mailman/listinfo/webkit-dev >
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