EricRahm

import json
import collections
import sys
import operator

from pprint import pprint

def path_total(data, path):
    totals = collections.defaultdict(int)
    totals_heap = collections.defaultdict(int)

EricRahm

Figuring out available memory on a device

adb shell cat /proc/meminfo

• MemTotal tells you how much device memory is available outside of drivers/kernel.
• MemFree tells you how much memory is currently available, checking this after booting should give you a rough guesstimate of what our max is.

To simulate what would happen in a low-memory situation you can adb shell kill <pid> each b2g process but b2g, (Nuwa), Homescreen (use b2g-ps to get a b2g process listing). Unfortunately Homescreen just comes back (it can be LMK'd though, so add it's USS to the MemFree total to get a better idea of an ideal MemFree value).

Get an overview of b2g application memory usage

EricRahm

On an 8 core, 32GB machine

• 2015/03/04 Nightly build
• 16 iterations, 8 at a time 2 loops
• numbers in KiB

   iteration,       Start,    Start+30,         Max,      Max+30,  MaxForceGC,         End,      End+30,  EndForceGC
           0,       99971,       87024,      392673,      377293,      345905,      311185,      203429,      171741
           1,      100135,       86956,      390233,      381165,      348737,      328053,      182673,      171661

EricRahm

Memory usage at each checkpoint iteration against 16 runs of the same build

• measurements in KiB

0
       MaxMemory:      387121,      386285,      395233,      383053,      392673
MaxMemorySettled:      378761,      377333,      381805,      376645,      377293
MaxMemoryForceGC:      342881,      343821,      348389,      345189,      345905
       EndMemory:      312305,      323221,      328185,      325237,      311185
EndMemorySettled:      164317,      196825,      178641,      201841,      203429

EricRahm

extension

auth/nsAuthGSSAPI.cpp

// Generate proper GSSAPI error messages from the major and
// minor status codes.
void
LogGssError(OM_uint32 maj_stat, OM_uint32 min_stat, const char *prefix)
{
    OM_uint32 new_stat;
    OM_uint32 msg_ctx = 0;

EricRahm

Currently:

typedef enum PRLogModuleLevel {
    PR_LOG_NONE = 0,                /* nothing */
    PR_LOG_ALWAYS = 1,              /* always printed */ <---- lies, damned lies
    PR_LOG_ERROR = 2,               /* error messages */
    PR_LOG_WARNING = 3,             /* warning messages */
    PR_LOG_DEBUG = 4,               /* debug messages */

 PR_LOG_NOTICE = PR_LOG_DEBUG, /* notice messages */ this one's weird

EricRahm

An attempt to get rid of lazy log instantiation boilerplate

#define LAZY_LOG_GETTER(fnx, name) \
    LogModule* fnx() { static LogModule* module = LogModule::CreateModule(name); return module; }

LAZY_LOG_GETTER(GetFooLog, "foo");

// ...

MOZ_LOG(GetFooLog(), LogLevel::Debug, ("Debugging the foo!"));

EricRahm

Reporting for MediaRawData:

Option 1: Report it in nsDocument::DocAddSizeOfExcludingThis (nsINode) HTMLMediaElement -> MediaSource -> SourceBuffer -> TrackBufferManager -> MediaRawData Pro: this should work Con: It would be rather generic under mDOMElementNodesSize

njn suggested expanding the struct to specify HTMLMediaElement specific stuff

• Reporter: https://dxr.mozilla.org/mozilla-central/source/dom/base/nsDocument.cpp#12646
• TracksBufferManager: https://dxr.mozilla.org/mozilla-central/source/dom/media/mediasource/TrackBuffersManager.cpp#1631

EricRahm

// pseudo-pythonish-cpp, whatever

total_reporters = len(reporters)

do_memory_reports:
  // this is on the main thread
  for r in reporters:
    main_thread_dispatch(new DoReportEvent(r));
  
  start_timer(on_report_done);

EricRahm

Currently two focuses:

• GetReportsState: roughly the interprocess state, keeps track of which subprocesses need to callled / are running. This is only in the parent process.
• CollectReportsState: intraprocess state, used in runnable, keeps track of which CollectReports calls are pending. This is in all processes and created in GetReportsForThisProcessExtended

  struct GetReportsState                                                                                               
  {
    uint32_t                             mGeneration;                                                                  
    bool                                 mAnonymize;