+++ /dev/null
-==================
- Memory Profiling
-==================
-
-Ceph MON, OSD and MDS can generate heap profiles using
-``tcmalloc``. To generate heap profiles, ensure you have
-``google-perftools`` installed::
-
- sudo apt-get install google-perftools
-
-The profiler dumps output to your ``log file`` directory (i.e.,
-``/var/log/ceph``). See `Logging and Debugging`_ for details.
-To view the profiler logs with Google's performance tools, execute the
-following::
-
- google-pprof --text {path-to-daemon} {log-path/filename}
-
-For example::
-
- $ ceph tell osd.0 heap start_profiler
- $ ceph tell osd.0 heap dump
- osd.0 tcmalloc heap stats:------------------------------------------------
- MALLOC: 2632288 ( 2.5 MiB) Bytes in use by application
- MALLOC: + 499712 ( 0.5 MiB) Bytes in page heap freelist
- MALLOC: + 543800 ( 0.5 MiB) Bytes in central cache freelist
- MALLOC: + 327680 ( 0.3 MiB) Bytes in transfer cache freelist
- MALLOC: + 1239400 ( 1.2 MiB) Bytes in thread cache freelists
- MALLOC: + 1142936 ( 1.1 MiB) Bytes in malloc metadata
- MALLOC: ------------
- MALLOC: = 6385816 ( 6.1 MiB) Actual memory used (physical + swap)
- MALLOC: + 0 ( 0.0 MiB) Bytes released to OS (aka unmapped)
- MALLOC: ------------
- MALLOC: = 6385816 ( 6.1 MiB) Virtual address space used
- MALLOC:
- MALLOC: 231 Spans in use
- MALLOC: 56 Thread heaps in use
- MALLOC: 8192 Tcmalloc page size
- ------------------------------------------------
- Call ReleaseFreeMemory() to release freelist memory to the OS (via madvise()).
- Bytes released to the OS take up virtual address space but no physical memory.
- $ google-pprof --text \
- /usr/bin/ceph-osd \
- /var/log/ceph/ceph-osd.0.profile.0001.heap
- Total: 3.7 MB
- 1.9 51.1% 51.1% 1.9 51.1% ceph::log::Log::create_entry
- 1.8 47.3% 98.4% 1.8 47.3% std::string::_Rep::_S_create
- 0.0 0.4% 98.9% 0.0 0.6% SimpleMessenger::add_accept_pipe
- 0.0 0.4% 99.2% 0.0 0.6% decode_message
- ...
-
-Another heap dump on the same daemon will add another file. It is
-convenient to compare to a previous heap dump to show what has grown
-in the interval. For instance::
-
- $ google-pprof --text --base out/osd.0.profile.0001.heap \
- ceph-osd out/osd.0.profile.0003.heap
- Total: 0.2 MB
- 0.1 50.3% 50.3% 0.1 50.3% ceph::log::Log::create_entry
- 0.1 46.6% 96.8% 0.1 46.6% std::string::_Rep::_S_create
- 0.0 0.9% 97.7% 0.0 26.1% ReplicatedPG::do_op
- 0.0 0.8% 98.5% 0.0 0.8% __gnu_cxx::new_allocator::allocate
-
-Refer to `Google Heap Profiler`_ for additional details.
-
-Once you have the heap profiler installed, start your cluster and
-begin using the heap profiler. You may enable or disable the heap
-profiler at runtime, or ensure that it runs continuously. For the
-following commandline usage, replace ``{daemon-type}`` with ``mon``,
-``osd`` or ``mds``, and replace ``{daemon-id}`` with the OSD number or
-the MON or MDS id.
-
-
-Starting the Profiler
----------------------
-
-To start the heap profiler, execute the following::
-
- ceph tell {daemon-type}.{daemon-id} heap start_profiler
-
-For example::
-
- ceph tell osd.1 heap start_profiler
-
-Alternatively the profile can be started when the daemon starts
-running if the ``CEPH_HEAP_PROFILER_INIT=true`` variable is found in
-the environment.
-
-Printing Stats
---------------
-
-To print out statistics, execute the following::
-
- ceph tell {daemon-type}.{daemon-id} heap stats
-
-For example::
-
- ceph tell osd.0 heap stats
-
-.. note:: Printing stats does not require the profiler to be running and does
- not dump the heap allocation information to a file.
-
-
-Dumping Heap Information
-------------------------
-
-To dump heap information, execute the following::
-
- ceph tell {daemon-type}.{daemon-id} heap dump
-
-For example::
-
- ceph tell mds.a heap dump
-
-.. note:: Dumping heap information only works when the profiler is running.
-
-
-Releasing Memory
-----------------
-
-To release memory that ``tcmalloc`` has allocated but which is not being used by
-the Ceph daemon itself, execute the following::
-
- ceph tell {daemon-type}{daemon-id} heap release
-
-For example::
-
- ceph tell osd.2 heap release
-
-
-Stopping the Profiler
----------------------
-
-To stop the heap profiler, execute the following::
-
- ceph tell {daemon-type}.{daemon-id} heap stop_profiler
-
-For example::
-
- ceph tell osd.0 heap stop_profiler
-
-.. _Logging and Debugging: ../log-and-debug
-.. _Google Heap Profiler: http://goog-perftools.sourceforge.net/doc/heap_profiler.html
Code Review / stor4nfv.git / blobdiff