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Chris Wilson c80274bb58 drm/i915: Downgrade NEWCLIENT to non-preemptive
Commit 1413b2bc07 ("drm/i915: Trim NEWCLIENT boosting") had the
intended consequence of not allowing a sequence of work that merely
crossed into a new engine the privilege to be promoted to NEWCLIENT
status. It also had the unintended consequence of actually making
NEWCLIENT effective on heavily oversubscribed transcode machines and
impacting upon their throughput.

If we consider a client packet composed of (rcsA, rcsB, vcs) and 30 of
those clients, using the NEWCLIENT boost that will be scheduled as

	rcsA x 30, (rcsB, vcs) x 30

where as before it would have been

	(rcsA, rcsB, vcs) x 30

That is with NEWCLIENT only boosting the first request of each client,
we would execute all rcsA requests prior to running on the vcs engines;
acruing a lot of dead time as compared to the previous case where the
vcs engine would be started in parallel to processing the second client.

The previous patch has the effect of delaying submission until it is
required by a third party (either the user with an explicit wait, or by
another client/engine). We reduce the NEWCLIENT bump to a mere WAIT,
which has the effect of removing its preemptive grant and reducing it to
the same level as any other user interaction -- that it will not be
promoted above the interengine dependencies, and so preventing NEWCLIENTS
from starving other engines. This a large nerf to the rrul properties of
the current NEWCLIENT, but it still does give prioritised submission to
new requests from light workloads.

References: b16c765122 ("drm/i915: Priority boost for new clients")
Fixes: 1413b2bc07 ("drm/i915: Trim NEWCLIENT boosting") # customer impact
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Cc: Dmitry Ermilov <dmitry.ermilov@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190515130052.4475-4-chris@chris-wilson.co.uk
(cherry picked from commit 68fc728b01)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
2019-05-20 18:28:22 +03:00
arch Merge branch 'akpm' (patches from Andrew) 2019-05-19 12:15:32 -07:00
block for-5.2/block-post-20190516 2019-05-16 19:08:15 -07:00
certs kexec, KEYS: Make use of platform keyring for signature verify 2019-02-04 17:34:07 -05:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2019-05-07 22:03:58 -07:00
Documentation Merge branch 'akpm' (patches from Andrew) 2019-05-19 12:15:32 -07:00
drivers drm/i915: Downgrade NEWCLIENT to non-preemptive 2019-05-20 18:28:22 +03:00
fs This pull request contains the following fixes for UBIFS: 2019-05-19 15:22:03 -07:00
include Merge branch 'akpm' (patches from Andrew) 2019-05-19 12:15:32 -07:00
init initramfs: don't free a non-existent initrd 2019-05-18 15:52:26 -07:00
ipc ipc: do cyclic id allocation for the ipc object. 2019-05-14 19:52:52 -07:00
kernel Merge branch 'akpm' (patches from Andrew) 2019-05-19 12:15:32 -07:00
lib slab: remove /proc/slab_allocators 2019-05-16 15:51:55 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'akpm' (patches from Andrew) 2019-05-19 12:15:32 -07:00
net treewide: prefix header search paths with $(srctree)/ 2019-05-18 11:49:57 +09:00
samples samples: guard sub-directories with CONFIG options 2019-05-18 11:29:01 +09:00
scripts kconfig: use 'else ifneq' for Makefile to improve readability 2019-05-19 09:34:35 +09:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-05-13 15:15:00 -07:00
sound sound fixes for 5.2-rc1 2019-05-17 13:57:54 -07:00
tools Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-05-19 11:20:22 -07:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt * ARM: support for SVE and Pointer Authentication in guests, PMU improvements 2019-05-17 10:33:30 -07:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap A reasonably busy cycle for docs, including: 2019-05-08 12:42:50 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Kbuild updates for v5.2 (2nd) 2019-05-19 11:53:58 -07:00
Makefile Linux 5.2-rc1 2019-05-19 15:47:09 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.