On 25-Jun-09, at 12:52 PM, Mike Belshe wrote: > Yeah, the APIs all have constraints. We end up walking the pages > and adding them up. See process_util_win.cc in the chromium tree. > Be sure to check about:memory and hover over the little "?" icons to > see what we measure.
This screen actually confuses me a little, as the Summary statistics don't match the summation of the process based statistics. Do you mean to say your summary statistics take into account the memory that's being shared across the various processes? If so, is there any command-line switch that will output those summary stats to console on a regular basis? > > If someone measures the "Private Bytes" counter, which uses the > PROCESS_MEMORY_COUNTERS_EX.PrivateUsage structure, that seems to map > to the Task Manager "Commit Size" which isn't the thing I believe we > want to measure. > > Right. Interestingly, as I watched this value change while webpages were loading, it tracked the same pattern of growth/decline as "Memory (Private Working Set)" in the Task Manager, though the values were usually about 2x or so more. I suppose this is due to the heap sharing you were speaking of earlier? > The "Working Set - Private" counter doesn't seem to have a structure > according to the MSDN document; that's what maps to the "Memory > (Private Working Set)" column in the TaskManager. > > Right, I think you have to use QueryWorkingSet, walk the pages and > categorize them yourself. OK, I can look into trying that. Though I'm wondering if it's worth the bother, as the meta-pattern, to me, is more interesting than the precise megabyte count. > > The closest thing I can find is the "Working Set" counter, which > uses the PROCESS_MEMORY_COUNTERS_EX.WorkingSetSize structure and > shows up in the Vista Task Manager as "Working Set (Memory)" > > For multi-proc browsers like chrome, this will way overstate RAM; > there is a good 5-6MB of shared working set in each process. So for > 10 tabs, you'd could an extra 50MB for Chrome if you do it this way. Looking both in Task Manager and about:memory, when I have 30 tabs open I'm not seeing 30 processes. Are you sure you're right about this point? > If you come up with a better way, please let me know! Well, I can tell you what we've done and what we're doing, just trying to get confidence on various metrics. We've replicated the "membuster" test we used around the release of Firefox 3 (see http://blog.pavlov.net/2008/03/11/firefox-3-memory-usage/ ) as a way of measuring Firefox's ability to hold a "steady" state of memory across a browsing session (ie: not leak) and then release that memory when the session ends (ie: not bogart system resources). The test: - runs on Windows 7, using Python and our Standalone Talos code to make measurements - uses a local web proxy to ensure we're always viewing the same web content - uses the JS at view-source:http://random.pavlov.net/membuster/index.html to: --- open 30 pages using window.open() calls --- load ~300 pages, opening and closing windows with each load (always 30 open) --- close all 30 windows when done cycling The whole while, we measure the amount of memory taken using the PROCESS_MEMORY_COUNTERS structure, summating over processes when multiple exist (as they do in the case of Internet Explorer 8 and Chrome 2) The results can be seen here, using both the PrivateUsage (shows as "Commit Size" in Windows 7 Task Manager) and WorkingSet (shows as "Working Set (Memory)" in Windows 7 Task Manager) counters: http://people.mozilla.com/~beltzner/images/private-usage.png http://people.mozilla.com/~beltzner/images/working-set.png The datapoint we wanted to get out of this was primarily about Firefox 3.5 vs Firefox 3.0.11, and as you can see we actually take slightly (7-10MB) more memory during the page cycling, but manage to release more when done. Safari had previously been unable to complete this test, but now does. I'd love to get your feedback on how we can improve our recording here. I think we're going to try and bundle together the test and files into an easier-to-use-tool than our delicately cobbled together solution, but if you wanted to try it yourself, here's a ZIP with the required code (needs Python 2.5 or later to be installed on your system): Once unzipped, enter the directory and run the following commands: \path\to\python\python.exe proxyserver.py -v -l -u proxy-cache.db \path\to\python\python.exe measure_any_windows_app.py > \path\to \resultsfile\resultsfile.txt You'll want to edit measure_any_windows_app.py to have the correct paths to the various applications, and you'll also want to make sure your browsers are set to use 127.0.0.1 port 8000 as a proxy (under Advanced > Network > Settings in Firefox, Internet Properties > Connections > LAN Settings for Chrome/IE/Safari) (Thanks to David Dahl for modifying the required files to get at those measurements) cheers, mike --~--~---------~--~----~------------~-------~--~----~ Chromium Developers mailing list: chromium-dev@googlegroups.com View archives, change email options, or unsubscribe: http://groups.google.com/group/chromium-dev -~----------~----~----~----~------~----~------~--~---
