821700 - slow Loading/Parsing of eBay WOW RSS Feed using built-in Feedreader

Status: RESOLVED INACTIVE

(Firefox Graveyard :: RSS Discovery and Preview, defect)

Description

[(mostly gone) XtC4UaLL [:xtc4uall]]

Using Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20121213 Firefox/20.0 ID:20121213030751 loading given RSS Feed is janky.

FWIW, I can repro the Issue back to using Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.0.19) Gecko/2010031422 Firefox/3.0.19 ID:2010031422 (didn't try older).

Not sure if this is a JS, FeedWriter.js/FeedProcessor.js or Site Issue.

SPS Profile:
http://people.mozilla.com/~bgirard/cleopatra/#report=8024166f6cbf78261afd6ea44fb24578ff50a393

Selection - Most time spent in:

    js::Interpret(JSContext *,js::StackFrame *,js::InterpMode)
    js::Interpret(JSContext *,js::StackFrame *,js::InterpMode)
    js::RunScript(JSContext *,JS::Handle<JSScript *>,js::StackFrame *)
    XPCOMUtils_QueryInterface() @ XPCOMUtils.jsm:322
    js::RunScript
    js::InvokeKernel(JSContext *,JS::CallArgs,js::MaybeConstruct)
    js::Invoke(JSContext *,JS::Value const &,JS::Value const &,unsigned int,JS::Value *,JS::Value *)
    js::CrossCompartmentWrapper::call(JSContext *,JSObject *,unsigned int,JS::Value *)
    proxy_Call
    js::InvokeKernel(JSContext *,JS::CallArgs,js::MaybeConstruct)
    js::Invoke(JSContext *,JS::Value const &,JS::Value const &,unsigned int,JS::Value *,JS::Value *)
    JS_CallFunctionValue(JSContext *,JSObject *,JS::Value,unsigned int,JS::Value *,JS::Value *)
    nsXPCWrappedJSClass::CallQueryInterfaceOnJSObject(JSContext *,JSObject *,nsID const &)
    nsXPCWrappedJSClass::DelegatedQueryInterface(nsXPCWrappedJS *,nsID const &,void * *)
    nsXPCWrappedJS::QueryInterface(nsID const &,void * *)
    nsXPTCStubBase::QueryInterface(nsID const &,void * *)
    nsScriptSecurityManager::CanCreateWrapper(JSContext *,nsID const &,nsISupports *,nsIClassInfo *,void * *)
    XPCWrappedNative::InitTearOff(XPCCallContext &,XPCWrappedNativeTearOff *,XPCNativeInterface *,int)
    XPCWrappedNative::GetNewOrUsed(XPCCallContext &,xpcObjectHelper &,XPCWrappedNativeScope *,XPCNativeInterface *,XPCWrappedNative * *)
    XPCConvert::NativeInterface2JSObject(XPCLazyCallContext &,JS::Value *,nsIXPConnectJSObjectHolder * *,xpcObjectHelper &,nsID const *,XPCNativeInterface * *,bool,tag_nsresult *)
    XPCConvert::NativeData2JS(XPCLazyCallContext &,JS::Value *,void const *,nsXPTType const &,nsID const *,tag_nsresult *)
    XPCVariant::VariantDataToJS(XPCLazyCallContext &,nsIVariant *,tag_nsresult *,JS::Value *)
    XPCConvert::NativeData2JS(XPCLazyCallContext &,JS::Value *,void const *,nsXPTType const &,nsID const *,tag_nsresult *)
    XPC_WN_CallMethod(JSContext *,unsigned int,JS::Value *)
    js::InvokeKernel(JSContext *,JS::CallArgs,js::MaybeConstruct)
    js::Interpret(JSContext *,js::StackFrame *,js::InterpMode)
    js::RunScript(JSContext *,JS::Handle<JSScript *>,js::StackFrame *)
    fieldsToObj() @ FeedProcessor.js:717
    Entry_normalize() @ FeedProcessor.js:424
    ......

Comment 1

[Boris Zbarsky [:bzbarsky]]

So first of all, it's a 3MB RSS file.

It takes me about 8 seconds from when I hit enter to when the RSS feed viewer shows the feed.

If I just fetch the file with wget, it takes 6+ seconds: 2 seconds while the server thinks about it, and then several seconds to download the 3MB at a rate far lower than my connection can actually do.

Past that, a bunch of time is spent parsing the XML, with a call into the feed handler JS on every single tag start and end and whatnot.  And then the JS does some expensive stuff, including ending up with a ton of exceptions thrown from calls through XPConnect (looks like to ThrowBadResult are at least 20% of the time, possibly a good bit more).

Comment 2

[BMO Automation]

Per policy at https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Inactive_Bugs. If this bug is not an enhancement request or a bug not present in a supported release of Firefox, then it may be reopened.