Well, for one thing, never perform I/O on the main thread. It really kills performance, as you witness. No amount of batching is going to be sufficient.
Also, why don't you use our stream classes?
Cheers,
David
On 24/10/14 14:36, Josip Maras wrote:
> Hi,
>
> I'm extending the Firefox source in order to log some information during web
> app execution, for example event, script executions, new element creations,
> removals, attribute modifications, etc. Since these things occur often, when
> I load a more demanding application (e.g. facebook), everything hangs for a
> while, because there is a large number of relatively small pieces of
> information being written to a file.
>
> Because of this, i was thinking of doing it in batches, having one global
> extern stream variable where all longs are added to, and when enough
> information gets accumulated to write it to a file, and avoid these hangings.
>
> Since I'm a noob C++ "programmer" I will paste some code of what i've done,
> just in case:
>
> I have one header file with the extern variable:
>
> -- FC_ExternStreamDeclaration.h --
>
> #ifndef FC_EXTERN_VAR_DECL_H
> #define FC_EXTERN_VAR_DECL_H
>
> #include <stdio.h>
> #include <sstream>
> #include <fstream>
>
> extern std::stringstream FC_LOG_STREAM;
>
> #endif //FC_EXTERN_VAR_DECL_H
>
>
> and one header with the logging functionality
>
> -- FC_Log.h --
>
> #pragma once
> #ifndef FC_LOG_H
> #define FC_LOG_H
>
> #include <stdio.h>
> #include <sstream>
> #include <fstream>
>
> #include "FC_ExternStreamDeclaration.h"
>
> inline void WriteToStream(const char** fragments, int length)
> {
> //add to stream
> //if stream big enough write to file
> }
> #endif //FC_LOG_H
>
> and in nsBrowserApp.cpp where the main function is defined, i define the
> variable and include the headers
>
> ----- nsBrowserApp.cpp ---
>
> #include "FC_ExternStreamDeclaration.h"
> #include "FC_Log.h"
>
> std::stringstream FC_LOG_STREAM;
>
> And then, in each file from which i do logging, i include the header files
> and call the WriteToStream function. For example, I'm doing it from
> Interpreter.cpp, Eval.cpp, nsINode.h, etc. (all over the code).
>
> And i thought that this will be enough. However, i get: error LNK2001
> unresolved external symbol stringstream FC_LOG_STREAM. If i define it there,
> the compilation succeeds, but I effectively get two different streams, one
> for the JavaScript execution, and the other for the DOM and the rest of the
> browser.
>
> I'm thinking this happens because these variables are in different dlls.
> I would be grateful for any tips about fixing it.
> Sorry for the long question.
>
> Thank you,
>
> Josip
> _______________________________________________
> dev-platform mailing list
> dev-platform@lists.mozilla.org
> https://lists.mozilla.org/listinfo/dev-platform
>
--
David Rajchenbach-Teller, PhD
Performance Team, Mozilla
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