From: Chris Wilson <chris@chris-wilson.co.uk>
To: John.C.Harrison@Intel.com
Cc: Intel-GFX@Lists.FreeDesktop.Org
Subject: Re: [PATCH v8 6/6] drm/i915: Cache last IRQ seqno to reduce IRQ overhead
Date: Fri, 13 May 2016 08:41:51 +0100 [thread overview]
Message-ID: <20160513074151.GI23271@nuc-i3427.alporthouse.com> (raw)
In-Reply-To: <1463087196-11688-7-git-send-email-John.C.Harrison@Intel.com>
On Thu, May 12, 2016 at 10:06:36PM +0100, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The notify function can be called many times without the seqno
> changing. Some are to prevent races due to the requirement of not
> enabling interrupts until requested. However, when interrupts are
> enabled the IRQ handler can be called multiple times without the
> ring's seqno value changing. E.g. two interrupts are generated by
> batch buffers completing in quick succession, the first call to the
> handler processes both completions but the handler still gets executed
> a second time. This patch reduces the overhead of these extra calls by
> caching the last processed seqno value and early exiting if it has not
> changed.
The idea is not to cache the last seqno (since that value is already
cached!) but to post new irq events.
Compare and contrast
https://patchwork.freedesktop.org/patch/85664/
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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next prev parent reply other threads:[~2016-05-13 7:41 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-12 21:06 [PATCH v8 0/6] Convert requests to use struct fence John.C.Harrison
2016-05-12 21:06 ` [PATCH v8 1/6] drm/i915: Add per context timelines to fence object John.C.Harrison
2016-05-13 7:39 ` Chris Wilson
2016-05-13 9:16 ` John Harrison
2016-05-18 12:22 ` Maarten Lankhorst
2016-05-18 12:49 ` John Harrison
2016-05-18 13:20 ` Maarten Lankhorst
2016-05-12 21:06 ` [PATCH v8 2/6] drm/i915: Convert requests to use struct fence John.C.Harrison
2016-05-12 21:06 ` [PATCH v8 3/6] drm/i915: Removed now redundant parameter to i915_gem_request_completed() John.C.Harrison
2016-05-12 21:06 ` [PATCH v8 4/6] drm/i915: Interrupt driven fences John.C.Harrison
2016-05-13 7:27 ` Chris Wilson
2016-05-13 9:19 ` John Harrison
2016-05-19 9:47 ` Chris Wilson
2016-05-19 9:24 ` Maarten Lankhorst
2016-05-12 21:06 ` [PATCH v8 5/6] drm/i915: Updated request structure tracing John.C.Harrison
2016-05-12 21:06 ` [PATCH v8 6/6] drm/i915: Cache last IRQ seqno to reduce IRQ overhead John.C.Harrison
2016-05-13 7:41 ` Chris Wilson [this message]
2016-05-12 21:10 ` ✗ Ro.CI.BAT: failure for Convert requests to use struct fence (rev5) Patchwork
2016-05-13 7:44 ` [PATCH v8 0/6] Convert requests to use struct fence Chris Wilson
2016-05-13 10:11 ` John Harrison
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