diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/block/bfq-iosched.txt | 29 | ||||
| -rw-r--r-- | Documentation/block/null_blk.txt | 4 | ||||
| -rw-r--r-- | Documentation/process/submit-checklist.rst | 27 | ||||
| -rw-r--r-- | Documentation/translations/ja_JP/SubmitChecklist | 22 |
4 files changed, 47 insertions, 35 deletions
diff --git a/Documentation/block/bfq-iosched.txt b/Documentation/block/bfq-iosched.txt index 98a8dd5ee385..1a0f2ac02eb6 100644 --- a/Documentation/block/bfq-iosched.txt +++ b/Documentation/block/bfq-iosched.txt @@ -20,13 +20,26 @@ for that device, by setting low_latency to 0. See Section 3 for details on how to configure BFQ for the desired tradeoff between latency and throughput, or on how to maximize throughput. -BFQ has a non-null overhead, which limits the maximum IOPS that a CPU -can process for a device scheduled with BFQ. To give an idea of the -limits on slow or average CPUs, here are, first, the limits of BFQ for -three different CPUs, on, respectively, an average laptop, an old -desktop, and a cheap embedded system, in case full hierarchical -support is enabled (i.e., CONFIG_BFQ_GROUP_IOSCHED is set), but -CONFIG_DEBUG_BLK_CGROUP is not set (Section 4-2): +As every I/O scheduler, BFQ adds some overhead to per-I/O-request +processing. To give an idea of this overhead, the total, +single-lock-protected, per-request processing time of BFQ---i.e., the +sum of the execution times of the request insertion, dispatch and +completion hooks---is, e.g., 1.9 us on an Intel Core i7-2760QM@2.40GHz +(dated CPU for notebooks; time measured with simple code +instrumentation, and using the throughput-sync.sh script of the S +suite [1], in performance-profiling mode). To put this result into +context, the total, single-lock-protected, per-request execution time +of the lightest I/O scheduler available in blk-mq, mq-deadline, is 0.7 +us (mq-deadline is ~800 LOC, against ~10500 LOC for BFQ). + +Scheduling overhead further limits the maximum IOPS that a CPU can +process (already limited by the execution of the rest of the I/O +stack). To give an idea of the limits with BFQ, on slow or average +CPUs, here are, first, the limits of BFQ for three different CPUs, on, +respectively, an average laptop, an old desktop, and a cheap embedded +system, in case full hierarchical support is enabled (i.e., +CONFIG_BFQ_GROUP_IOSCHED is set), but CONFIG_DEBUG_BLK_CGROUP is not +set (Section 4-2): - Intel i7-4850HQ: 400 KIOPS - AMD A8-3850: 250 KIOPS - ARM CortexTM-A53 Octa-core: 80 KIOPS @@ -566,3 +579,5 @@ applications. Unset this tunable if you need/want to control weights. Slightly extended version: http://algogroup.unimore.it/people/paolo/disk_sched/bfq-v1-suite- results.pdf + +[3] https://github.com/Algodev-github/S diff --git a/Documentation/block/null_blk.txt b/Documentation/block/null_blk.txt index 4cad1024fff7..41f0a3d33bbd 100644 --- a/Documentation/block/null_blk.txt +++ b/Documentation/block/null_blk.txt @@ -93,3 +93,7 @@ zoned=[0/1]: Default: 0 zone_size=[MB]: Default: 256 Per zone size when exposed as a zoned block device. Must be a power of two. + +zone_nr_conv=[nr_conv]: Default: 0 + The number of conventional zones to create when block device is zoned. If + zone_nr_conv >= nr_zones, it will be reduced to nr_zones - 1. diff --git a/Documentation/process/submit-checklist.rst b/Documentation/process/submit-checklist.rst index 367353c54949..c88867b173d9 100644 --- a/Documentation/process/submit-checklist.rst +++ b/Documentation/process/submit-checklist.rst @@ -72,47 +72,44 @@ and elsewhere regarding submitting Linux kernel patches. 13) Has been build- and runtime tested with and without ``CONFIG_SMP`` and ``CONFIG_PREEMPT.`` -14) If the patch affects IO/Disk, etc: has been tested with and without - ``CONFIG_LBDAF.`` +16) All codepaths have been exercised with all lockdep features enabled. -15) All codepaths have been exercised with all lockdep features enabled. +17) All new ``/proc`` entries are documented under ``Documentation/`` -16) All new ``/proc`` entries are documented under ``Documentation/`` - -17) All new kernel boot parameters are documented in +18) All new kernel boot parameters are documented in ``Documentation/admin-guide/kernel-parameters.rst``. -18) All new module parameters are documented with ``MODULE_PARM_DESC()`` +19) All new module parameters are documented with ``MODULE_PARM_DESC()`` -19) All new userspace interfaces are documented in ``Documentation/ABI/``. +20) All new userspace interfaces are documented in ``Documentation/ABI/``. See ``Documentation/ABI/README`` for more information. Patches that change userspace interfaces should be CCed to linux-api@vger.kernel.org. -20) Check that it all passes ``make headers_check``. +21) Check that it all passes ``make headers_check``. -21) Has been checked with injection of at least slab and page-allocation +22) Has been checked with injection of at least slab and page-allocation failures. See ``Documentation/fault-injection/``. If the new code is substantial, addition of subsystem-specific fault injection might be appropriate. -22) Newly-added code has been compiled with ``gcc -W`` (use +23) Newly-added code has been compiled with ``gcc -W`` (use ``make EXTRA_CFLAGS=-W``). This will generate lots of noise, but is good for finding bugs like "warning: comparison between signed and unsigned". -23) Tested after it has been merged into the -mm patchset to make sure +24) Tested after it has been merged into the -mm patchset to make sure that it still works with all of the other queued patches and various changes in the VM, VFS, and other subsystems. -24) All memory barriers {e.g., ``barrier()``, ``rmb()``, ``wmb()``} need a +25) All memory barriers {e.g., ``barrier()``, ``rmb()``, ``wmb()``} need a comment in the source code that explains the logic of what they are doing and why. -25) If any ioctl's are added by the patch, then also update +26) If any ioctl's are added by the patch, then also update ``Documentation/ioctl/ioctl-number.txt``. -26) If your modified source code depends on or uses any of the kernel +27) If your modified source code depends on or uses any of the kernel APIs or features that are related to the following ``Kconfig`` symbols, then test multiple builds with the related ``Kconfig`` symbols disabled and/or ``=m`` (if that option is available) [not all of these at the diff --git a/Documentation/translations/ja_JP/SubmitChecklist b/Documentation/translations/ja_JP/SubmitChecklist index 60c7c35ac517..b42220d3d46c 100644 --- a/Documentation/translations/ja_JP/SubmitChecklist +++ b/Documentation/translations/ja_JP/SubmitChecklist @@ -74,38 +74,34 @@ Linux カーネルパッチ投稿者向けチェックリスト 13: CONFIG_SMP, CONFIG_PREEMPT を有効にした場合と無効にした場合の両方で ビルドした上、動作確認を行ってください。 -14: もしパッチがディスクのI/O性能などに影響を与えるようであれば、 - 'CONFIG_LBDAF'オプションを有効にした場合と無効にした場合の両方で - テストを実施してみてください。 +14: lockdepの機能を全て有効にした上で、全てのコードパスを評価してください。 -15: lockdepの機能を全て有効にした上で、全てのコードパスを評価してください。 - -16: /proc に新しいエントリを追加した場合には、Documentation/ 配下に +15: /proc に新しいエントリを追加した場合には、Documentation/ 配下に 必ずドキュメントを追加してください。 -17: 新しいブートパラメータを追加した場合には、 +16: 新しいブートパラメータを追加した場合には、 必ずDocumentation/admin-guide/kernel-parameters.rst に説明を追加してください。 -18: 新しくmoduleにパラメータを追加した場合には、MODULE_PARM_DESC()を +17: 新しくmoduleにパラメータを追加した場合には、MODULE_PARM_DESC()を 利用して必ずその説明を記述してください。 -19: 新しいuserspaceインタフェースを作成した場合には、Documentation/ABI/ に +18: 新しいuserspaceインタフェースを作成した場合には、Documentation/ABI/ に Documentation/ABI/README を参考にして必ずドキュメントを追加してください。 -20: 'make headers_check'を実行して全く問題がないことを確認してください。 +19: 'make headers_check'を実行して全く問題がないことを確認してください。 -21: 少なくともslabアロケーションとpageアロケーションに失敗した場合の +20: 少なくともslabアロケーションとpageアロケーションに失敗した場合の 挙動について、fault-injectionを利用して確認してください。 Documentation/fault-injection/ を参照してください。 追加したコードがかなりの量であったならば、サブシステム特有の fault-injectionを追加したほうが良いかもしれません。 -22: 新たに追加したコードは、`gcc -W'でコンパイルしてください。 +21: 新たに追加したコードは、`gcc -W'でコンパイルしてください。 このオプションは大量の不要なメッセージを出力しますが、 "warning: comparison between signed and unsigned" のようなメッセージは、 バグを見つけるのに役に立ちます。 -23: 投稿したパッチが -mm パッチセットにマージされた後、全ての既存のパッチや +22: 投稿したパッチが -mm パッチセットにマージされた後、全ての既存のパッチや VM, VFS およびその他のサブシステムに関する様々な変更と、現時点でも共存 できることを確認するテストを行ってください。 |