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Paolo Valente
cfd69712a1
This patch introduces an heuristic that reduces latency when the I/O-request pool is saturated. This goal is achieved by disabling device idling, for non-weight-raised queues, when there are weight- raised queues with pending or in-flight requests. In fact, as explained in more detail in the comment on the function bfq_bfqq_may_idle(), this reduces the rate at which processes associated with non-weight-raised queues grab requests from the pool, thereby increasing the probability that processes associated with weight-raised queues get a request immediately (or at least soon) when they need one. Along the same line, if there are weight-raised queues, then this patch halves the service rate of async (write) requests for non-weight-raised queues. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
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.