27a96f1f34
In release-6 rpc/rpc-lib (libgfrpc) added the function
get_rightmost_set_bit() which calls log2(3), a call that takes
a floating point parameter and returns a floating point.
It's used thusly:
right_most_unset_bit = get_rightmost_set_bit(...);
(So is it really the right-most unset bit, or the right-most set bit?)
It's unclear to me whether this is in the data path or not. If it is,
it's rather scary to think about integer-to-float and float-to-integer
conversions and slow calls to libm functions in the data path.
gcc and clang have __builtin_ctz() which returns the same result as
get_rightmost_set_bit(), and does it substantially faster. Approx
20M iterations of get_rightmost_set_bit() took ~33sec of wall clock
time on my devel machine, while 20M iterations of __builtin_ctz()
took < 9sec; get_rightmost_set_bit() is 3x slower than __builtin_ctz().
And as a side benefit, we can again eliminate the need to link libgfrpc
with libm.
Change-Id: If9e7e80874577c52223f8125b385fc930de20699
fixes: bz#1692957
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>
Gluster
Gluster is a software defined distributed storage that can scale to several petabytes. It provides interfaces for object, block and file storage.
Development
Contributions to gluster in the form of patches and new feature additions can be made by following steps outlined at Developers Guide.
Documentation
The Gluster documentation can be found at Gluster Docs.
Deployment
Quick instructions to build and install can be found in INSTALL file.
Testing
GlusterFS source contains some functional tests under tests/ directory. All
these tests are run against every patch submitted for review. If you want your
patch to be tested, please add a .t test file as part of your patch submission.
You can also submit a patch to only add a .t file for the test case you are
aware of.
To run these tests, on your test-machine, just run ./run-tests.sh. Don't run
this on a machine where you have 'production' glusterfs is running, as it would
blindly kill all gluster processes in each runs.
If you are sending a patch, and want to validate one or few specific tests, then run a single test by running the below command.
bash# /bin/bash ${path_to_gluster}/tests/basic/rpc-coverage.t
You can also use prove tool if available in your machine, as follows.
bash# prove -vmfe '/bin/bash' ${path_to_gluster}/tests/basic/rpc-coverage.t
Maintainers
The list of Gluster maintainers is available in MAINTAINERS file.
License
Gluster is dual licensed under GPLV2 and LGPLV3+.
Please visit the Gluster Home Page to find out more about Gluster.