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This flag determines whether the thread should currently process the work in the thread->todo worklist. The prime usecase for this is improving the performance of synchronous transactions: all synchronous transactions post a BR_TRANSACTION_COMPLETE to the calling thread, but there's no reason to return that command to userspace right away - userspace anyway needs to wait for the reply. Likewise, a synchronous transaction that contains a binder object can cause a BC_ACQUIRE/BC_INCREFS to be returned to userspace; since the caller must anyway hold a strong/weak ref for the duration of the call, postponing these commands until the reply comes in is not a problem. Note that this flag is not used to determine whether a thread can handle process work; a thread should never pick up process work when thread work is still pending. Before patch: ------------------------------------------------------------------ Benchmark Time CPU Iterations ------------------------------------------------------------------ BM_sendVec_binderize/4 45959 ns 20288 ns 34351 BM_sendVec_binderize/8 45603 ns 20080 ns 34909 BM_sendVec_binderize/16 45528 ns 20113 ns 34863 BM_sendVec_binderize/32 45551 ns 20122 ns 34881 BM_sendVec_binderize/64 45701 ns 20183 ns 34864 BM_sendVec_binderize/128 45824 ns 20250 ns 34576 BM_sendVec_binderize/256 45695 ns 20171 ns 34759 BM_sendVec_binderize/512 45743 ns 20211 ns 34489 BM_sendVec_binderize/1024 46169 ns 20430 ns 34081 After patch: ------------------------------------------------------------------ Benchmark Time CPU Iterations ------------------------------------------------------------------ BM_sendVec_binderize/4 42939 ns 17262 ns 40653 BM_sendVec_binderize/8 42823 ns 17243 ns 40671 BM_sendVec_binderize/16 42898 ns 17243 ns 40594 BM_sendVec_binderize/32 42838 ns 17267 ns 40527 BM_sendVec_binderize/64 42854 ns 17249 ns 40379 BM_sendVec_binderize/128 42881 ns 17288 ns 40427 BM_sendVec_binderize/256 42917 ns 17297 ns 40429 BM_sendVec_binderize/512 43184 ns 17395 ns 40411 BM_sendVec_binderize/1024 43119 ns 17357 ns 40432 Signed-off-by: Martijn Coenen <maco@android.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. 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.