Use BlocksRingBuffer in ProfileBuffer
Categories
(Core :: Gecko Profiler, task, P2)
Tracking
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| Tracking | Status | |
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| firefox71 | --- | fixed |
People
(Reporter: mozbugz, Assigned: mozbugz)
References
Details
Attachments
(4 files, 1 obsolete file)
Instead of implementing its own circular buffer, ProfileBuffer will now use BlocksRingBuffer.
That BlocksRingBuffer will be stored in CorePS (in platform.cpp) because it will need to live even when the profiler is not enabled (because some slightly-racy function like profiler_add_marker may still try to store some data shortly after the profiler has been disabled).
Because BlocksRingBuffer is stored outside of ProfileBuffer, ProfilerBacktrace will need to also store the BlocksRingBuffer that its ProfileBuffer uses.
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Assignee | |
Comment 1•5 years ago
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This just replaces ProfileBuffer's self-managed circular buffer with a
BlocksRingBuffer.
Depends on D43420
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Assignee | |
Comment 2•5 years ago
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BlocksRingBuffers will be stored outside of ProfileBuffers, as we need to be
able to safely access the underlying buffers when profilers are not enabled.
Depends on D43421
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Assignee | |
Comment 3•5 years ago
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Because any thread could be holding the BlocksRingBuffer lock (e.g., when it
will store markers), we need to ensure that the sampler thread takes that lock
before stopping a thread, because the sampler then needs to lock the buffer when
storing its data.
Depends on D43422
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Updated•5 years ago
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Assignee | |
Comment 4•5 years ago
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Add some stats (off by default) around streaming JSON, as the following patches
may affect it.
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Assignee | |
Comment 5•5 years ago
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Now that we are using a byte-oriented BlocksRingBuffer instead of an array of
9-byte ProfileBufferEntry's, internally the profiler sets the buffer size in
bytes. However all external users (popup, tests, etc.) still assume that the
requested capacity is in entries!
To limit the amount of changes, we will keep assuming externally-visible
capacities are in entries, and convert them to bytes.
Even though entries used to be 9 bytes each, and BlocksRingBuffer adds 1 byte
for the entry size, some entries actually need less space (e.g., 32-bit numbers
now take 6 bytes instead of 9), so converting to less than 9 bytes per entry is
acceptable.
We are settling on 8 bytes per entry: It's close to 9, and it's a power of two;
since the effective number of entries was a power of two, and BlocksRingBuffer
also uses a power of two size in bytes, this convertion keeps sizes in powers of
two.
Depends on D43421
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Updated•5 years ago
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Pushed by gsquelart@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/ec72dfc7301e AUTO_PROFILER_STATS(locked_profiler_stream_json_for_this_process) - r=gregtatum https://hg.mozilla.org/integration/autoland/rev/d7ee4148aad9 Use BlocksRingBuffer in ProfileBuffer - r=gregtatum https://hg.mozilla.org/integration/autoland/rev/366030bd2d84 Assume capacity is in 8-byte entries - r=gregtatum https://hg.mozilla.org/integration/autoland/rev/b6d73f5042a7 Store BlocksRingBuffer outside of ProfileBuffer - r=gregtatum
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Comment 7•5 years ago
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Backed out 21 changesets (Bug 1578327, Bug 1575448, Bug 1580091, Bug 1576554, Bug 1581049, Bug 1576551, Bug 1578329, Bug 1576555) for platform.cpp related bustage
Backout link: https://hg.mozilla.org/integration/autoland/rev/9c10aac0356842219e95d1f6deb0bf7e7baed334
Failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=266985776&repo=autoland&lineNumber=53923
Pushed by gsquelart@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/af093f06fb74 AUTO_PROFILER_STATS(locked_profiler_stream_json_for_this_process) - r=gregtatum https://hg.mozilla.org/integration/autoland/rev/524f84e0fc78 Use BlocksRingBuffer in ProfileBuffer - r=gregtatum https://hg.mozilla.org/integration/autoland/rev/3dfc76ea7bd9 Assume capacity is in 8-byte entries - r=gregtatum https://hg.mozilla.org/integration/autoland/rev/fd3a29881783 Store BlocksRingBuffer outside of ProfileBuffer - r=gregtatum
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Comment 9•5 years ago
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| bugherder | ||
https://hg.mozilla.org/mozilla-central/rev/af093f06fb74
https://hg.mozilla.org/mozilla-central/rev/524f84e0fc78
https://hg.mozilla.org/mozilla-central/rev/3dfc76ea7bd9
https://hg.mozilla.org/mozilla-central/rev/fd3a29881783
Description
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