7774e77ebe
This patch replaces the ctrl->namespaces tracking from linked list to xarray and improves the performance when accessing one namespce :- XArray vs Default:- IOPS and BW (more the better) increase BW (~1.8%):- --------------------------------------------------- XArray :- read: IOPS=160k, BW=626MiB/s (656MB/s)(18.3GiB/30001msec) read: IOPS=160k, BW=626MiB/s (656MB/s)(18.3GiB/30001msec) read: IOPS=162k, BW=631MiB/s (662MB/s)(18.5GiB/30001msec) Default:- read: IOPS=156k, BW=609MiB/s (639MB/s)(17.8GiB/30001msec) read: IOPS=157k, BW=613MiB/s (643MB/s)(17.0GiB/30001msec) read: IOPS=160k, BW=626MiB/s (656MB/s)(18.3GiB/30001msec) Submission latency (less the better) decrease (~8.3%):- ------------------------------------------------------- XArray:- slat (usec): min=7, max=8386, avg=11.19, stdev=5.96 slat (usec): min=7, max=441, avg=11.09, stdev=4.48 slat (usec): min=7, max=1088, avg=11.21, stdev=4.54 Default :- slat (usec): min=8, max=2826.5k, avg=23.96, stdev=3911.50 slat (usec): min=8, max=503, avg=12.52, stdev=5.07 slat (usec): min=8, max=2384, avg=12.50, stdev=5.28 CPU Usage (less the better) decrease (~5.2%):- ---------------------------------------------- XArray:- cpu : usr=1.84%, sys=18.61%, ctx=949471, majf=0, minf=250 cpu : usr=1.83%, sys=18.41%, ctx=950262, majf=0, minf=237 cpu : usr=1.82%, sys=18.82%, ctx=957224, majf=0, minf=234 Default:- cpu : usr=1.70%, sys=19.21%, ctx=858196, majf=0, minf=251 cpu : usr=1.82%, sys=19.98%, ctx=929720, majf=0, minf=227 cpu : usr=1.83%, sys=20.33%, ctx=947208, majf=0, minf=235. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.