Linux kernel for uConsole
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Chris Wilson cd46c545b7 drm/i915/breadcrumbs: Reduce signaler rbtree to a sorted list
The goal here is to try and reduce the latency of signaling additional
requests following the wakeup from interrupt by reducing the list of
to-be-signaled requests from an rbtree to a sorted linked list. The
original choice of using an rbtree was to facilitate random insertions
of request into the signaler while maintaining a sorted list. However,
if we assume that most new requests are added when they are submitted,
we see those new requests in execution order making a insertion sort
fast, and the reduction in overhead of each signaler iteration
significant.

Since commit 56299fb7d9 ("drm/i915: Signal first fence from irq handler
if complete"), we signal most fences directly from notify_ring() in the
interrupt handler greatly reducing the amount of work that actually
needs to be done by the signaler kthread. All the thread is then
required to do is operate as the bottom-half, cleaning up after the
interrupt handler and preparing the next waiter. This includes signaling
all later completed fences in a saturated system, but on a mostly idle
system we only have to rebuild the wait rbtree in time for the next
interrupt. With this de-emphasis of the signaler's role, we want to
rejig it's datastructures to reduce the amount of work we require to
both setup the signal tree and maintain it on every interrupt.

References: 56299fb7d9 ("drm/i915: Signal first fence from irq handler if complete")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180222092545.17216-1-chris@chris-wilson.co.uk
2018-03-06 12:12:45 +00:00
arch unify {de,}mangle_poll(), get rid of kernel-side POLL... 2018-02-11 14:37:22 -08:00
block vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
certs
crypto vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
Documentation Merge drm-next into drm-intel-next-queued (this time for real) 2018-03-01 11:14:24 +02:00
drivers drm/i915/breadcrumbs: Reduce signaler rbtree to a sorted list 2018-03-06 12:12:45 +00:00
firmware
fs vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
include Merge drm-next into drm-intel-next-queued (this time for real) 2018-03-01 11:14:24 +02:00
init membarrier: Provide core serializing command, *_SYNC_CORE 2018-02-05 21:35:03 +01:00
ipc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
kernel vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
lib Kbuild updates for v4.16 (2nd) 2018-02-09 19:32:41 -08:00
LICENSES
mm vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
net vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
samples sample/bpf: fix erspan metadata 2018-02-06 11:32:49 -05:00
scripts Kbuild updates for v4.16 (2nd) 2018-02-09 19:32:41 -08:00
security vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
sound vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-09 15:34:18 -08:00
usr
virt vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS drm-misc-next for 4.17: 2018-02-16 09:29:27 +10:00
Makefile Linux 4.16-rc1 2018-02-11 15:04:29 -08:00
README

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.