Kernel Source and devicetree for NOTHING Phone(3a) and Phone(3a)Pro
c03be752d3
Joel Fernandes found that the synchronize_rcu_tasks() was taking a significant amount of time. He demonstrated it with the following test: # cd /sys/kernel/tracing # while [ 1 ]; do x=1; done & # echo '__schedule_bug:traceon' > set_ftrace_filter # time echo '!__schedule_bug:traceon' > set_ftrace_filter; real 0m1.064s user 0m0.000s sys 0m0.004s Where it takes a little over a second to perform the synchronize, because there's a loop that waits 1 second at a time for tasks to get through their quiescent points when there's a task that must be waited for. After discussion we came up with a simple way to wait for holdouts but increase the time for each iteration of the loop but no more than a full second. With the new patch we have: # time echo '!__schedule_bug:traceon' > set_ftrace_filter; real 0m0.131s user 0m0.000s sys 0m0.004s Which drops it down to 13% of what the original wait time was. Link: http://lkml.kernel.org/r/20180523063815.198302-2-joel@joelfernandes.org Reported-by: Joel Fernandes (Google) <joel@joelfernandes.org> Suggested-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.