René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Transfer progress notifications are prohibitively slow","articleBody":"Having even an empty transfer progress function for fetches adds a large amount of overhead. In the code below, for example, on the nodegit repo itself, specifying a transfer progress function adds about 38s for me.\n\nThe progress function is called once for each object fetched from the repository: about 25,000 times for the nodegit repo as of today. That would indicate an overhead of about 1.5ms for calling from C++ into JavaScript (running on a 3.1ghz i7). This amount of overhead feels a little high; I wonder if there might be some room for optimizing the JS/C++ binding/bridge code.\n\nEven if significantly optimized (e.g., by a factor of 10), the overhead of calling from C++ into JS is probably high enough to be prohibitive; it might be good to be able to provide some conflation so that the progress function is called no more than a specified frequency (e.g., no more than once every 100ms).\n\nIf no one has an easy answer for this, I would be more than happy to lend a hand (I have a lot of experience with v8).\n\nSample code:\n\n```\nconst NodeGit = require(\"nodegit\");\n\nconsole.time(\"no-progress\");\n\nNodeGit.Clone(\"https://github.com/nodegit/nodegit.git\", \"no-progress\")\n.then(function () {\n    console.timeEnd(\"no-progress\");\n    console.time(\"progress\");\n    var options = new NodeGit.CloneOptions();\n    var fetchOpts = new NodeGit.FetchOptions();\n    options.fetchOpts = fetchOpts;\n    var callbacks = new NodeGit.RemoteCallbacks();\n    fetchOpts.callbacks = callbacks;\n    callbacks.transferProgress = function () {\n    };\n    return NodeGit.Clone(\"https://github.com/nodegit/nodegit.git\",\n                         \"progress\",\n                         options);\n}).done(function () {\n    console.timeEnd(\"progress\");\n    process.exit(0);\n});\n```\n","author":{"url":"https://github.com/bpeabody","@type":"Person","name":"bpeabody"},"datePublished":"2016-02-24T20:26:32.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/919/nodegit/issues/919"}