Commits on Dec 20, 2013

1. osd: conditionally disable dlclose of erasure code plugins …

   When profiling, tools such as valgrind --tool=callgrind require that the
   dynamically loaded libraries are not dlclosed so they can collect usage
   information.
   
   The public ErasureCodePluginRegistry::disable_dlclose boolean is introduced
   for this purpose.
   
   Signed-off-by: Loic Dachary <loic@dachary.org>

   Loic Dachary committed Dec 20, 2013
   Copy the full SHA

   ff9455b View commit details

   Browse the repository at this point in the history

2. osd: better performances for the erasure code example …

   The XOR based example is ten times slower than it could because it uses
   the buffer::ptr[] operator. Use a temporary char * instead. It performs
   as well as jerasure Reed Solomon when decoding with a single erasure:
   
   $ ceph_erasure_code_benchmark \
      --plugin example  --parameter erasure-code-directory=.libs \
      --parameter erasure-code-technique=example \
      --parameter erasure-code-k=2 --parameter erasure-code-m=1 \
      --erasure 1 --workload decode --iterations 5000
   8.095007	5GB
   
   $ ceph_erasure_code_benchmark \
      --plugin jerasure  --parameter erasure-code-directory=.libs \
      --parameter erasure-code-technique=reed_sol_van \
      --parameter erasure-code-k=10 --parameter erasure-code-m=6 \
      --erasure 1 --workload decode --iterations 5000
   7.870990	5GB
   
   Signed-off-by: Loic Dachary <loic@dachary.org>

   Loic Dachary committed Dec 20, 2013
   Copy the full SHA

   c7d8ba7 View commit details

   Browse the repository at this point in the history

3. osd: set erasure code packet size default to 2048 …

   As shown in
   https://www.usenix.org/legacy/events/fast09/tech/full_papers/plank/plank_html/
   under "Impact of the Packet Size", the optimal for is in the order of 1k
   rather than the current default of 8. Benchmarks are required to find
   the actual optimum.
   
   Signed-off-by: Loic Dachary <loic@dachary.org>

   Loic Dachary committed Dec 20, 2013
   Copy the full SHA

   a36bc5f View commit details

   Browse the repository at this point in the history

4. osd: erasure code benchmark tool …

   Implement the ceph_erasure_code_benchmark utility to:
   
   * load an erasure code plugin
   
   * loop over the encode/decode function using the parameters from the
     command line
   
   * print the number of bytes encoded/decoded and the time to process
   
   When decoding, random chunks ( as set with --erasures ) are lost on each
   run.
   
   For instance:
   
       $ ceph_erasure_code_benchmark \
          --plugin jerasure \
          --parameter erasure-code-directory=.libs \
          --parameter erasure-code-technique=reed_sol_van \
          --parameter erasure-code-k=2 \
          --parameter erasure-code-m=2 \
          --workload decode \
          --erasures 2 \
          --iterations 1000
       0.964759	1048576
   
   shows 1GB is decoded in 1second.
   
   It is intended to be used by other scripts to present a human readable
   output or detect performance regressions.
   
   Signed-off-by: Loic Dachary <loic@dachary.org>

   Loic Dachary committed Dec 20, 2013
   Copy the full SHA

   a619fe9 View commit details

   Browse the repository at this point in the history

5. osd: erasure code benchmark workunit …

   Display benchmark results for the default erasure code plugins, in a tab
   separated CSV file. The first two column contain the amount of KB
   that were coded or decoded, for a given combination of parameters
   displayed in the following fields.
   
   seconds	KB	plugin	k	m	work.	iter.	size	eras.
   1.2	10	example	2	1	encode	10	1024	0
   0.5	10	example	2	1	decode	10	1024	1
   
   It can be used as input for a human readable report. It is also intented
   to be used to show if a given version of an erasure code plugin performs
   better than another.
   
   The last column ( not shown above for brievety ) is the exact command
   that was run to produce the result so it can be copy / pasted to
   reproduce them or to profile.
   
   Only the jerasure techniques mentionned in
   https://www.usenix.org/legacy/events/fast09/tech/full_papers/plank/plank_html/
   are benchmarked, the others are assumed to be less interesting.
   
   Signed-off-by: Loic Dachary <loic@dachary.org>

   Loic Dachary committed Dec 20, 2013
   Copy the full SHA

   81dee1b View commit details

   Browse the repository at this point in the history

6. osd: erasure code benchmark is installed is part of ceph-test …

   Add to the packaging for RPMs and DEBs
   
   Signed-off-by: Loic Dachary <loic@dachary.org>

   Loic Dachary committed Dec 20, 2013
   Copy the full SHA

   42b4fe1 View commit details

   Browse the repository at this point in the history

7. osd: git ignore erasure code benchmark binary …

   Signed-off-by: Loic Dachary <loic@dachary.org>

   Loic Dachary committed Dec 20, 2013
   Copy the full SHA

   03693ac View commit details

   Browse the repository at this point in the history