mainlining shenanigans
7812472f97
One of the methods with which bfq boosts throughput is by merging queues. One of the merging variants in bfq is the stable merge. This mechanism is activated between two queues only if they are created within a certain maximum time T1 from each other. Merging can happen soon or be delayed. In the second case, before merging, bfq needs to evaluate a throughput-boost parameter that indicates whether the queue generates a high throughput is served alone. Merging occurs when this throughput-boost is not high enough. In particular, this parameter is evaluated and late merging may occur only after at least a time T2 from the creation of the queue. Currently T1 and T2 are set to 180ms and 200ms, respectively. In this way the merging mechanism rarely occurs because time is not enough. This results in a noticeable lowering of the overall throughput with some workloads (see the example below). This commit introduces two constants bfq_activation_stable_merging and bfq_late_stable_merging in order to increase the duration of T1 and T2. Both the stable merging activation time and the late merging time are set to 600ms. This value has been experimentally evaluated using sqlite benchmark in the Phoronix Test Suite on a HDD. The duration of the benchmark before this fix was 111.02s, while now it has reached 97.02s, a better result than that of all the other schedulers. Signed-off-by: Pietro Pedroni <pedroni.pietro.96@gmail.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Link: https://lore.kernel.org/r/20210619140948.98712-5-paolo.valente@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| 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 | ||
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| 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.
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.