From: Michel Thierry <michel.thierry@intel.com>
To: Chris Wilson <chris@chris-wilson.co.uk>, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915/execlists: Drop preemption arbitrations points along the ring
Date: Thu, 3 May 2018 13:00:13 -0700 [thread overview]
Message-ID: <07c4673e-bbd0-b4ee-35df-c2220af60fd4@intel.com> (raw)
In-Reply-To: <20180503195416.22498-1-chris@chris-wilson.co.uk>
On 5/3/2018 12:54 PM, Chris Wilson wrote:
> Limit the arbitration (where preemption may occur) to inside the batch,
> and prevent it from happening on the pipecontrols/flushes we use to
> write the breadcrumb seqno. Once the user batch is complete, we have
> nothing left to do but serialise and emit the breadcrumb; switching
> contexts at this point is futile so don't.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Michał Winiarski <michal.winiarski@intel.com>
> Cc: Michel Thierry <michel.thierry@intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> ---
>
> Michał and Michel,
> please take a look and see if you can think of any objections.
No objections, I was only thinking what would happen if we arm the
watchdog (and we decide timeout != reset the engine) and forgot to write
a reply. For the record, I think it'd be ok anyway.
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
> -Chris
>
> ---
> drivers/gpu/drm/i915/intel_lrc.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 3d747d1c3d4d..9f3cce022b2d 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -1933,7 +1933,7 @@ static int gen8_emit_bb_start(struct i915_request *rq,
> rq->ctx->ppgtt->pd_dirty_rings &= ~intel_engine_flag(rq->engine);
> }
>
> - cs = intel_ring_begin(rq, 4);
> + cs = intel_ring_begin(rq, 6);
> if (IS_ERR(cs))
> return PTR_ERR(cs);
>
> @@ -1962,6 +1962,9 @@ static int gen8_emit_bb_start(struct i915_request *rq,
> (flags & I915_DISPATCH_RS ? MI_BATCH_RESOURCE_STREAMER : 0);
> *cs++ = lower_32_bits(offset);
> *cs++ = upper_32_bits(offset);
> +
> + *cs++ = MI_ARB_ON_OFF | MI_ARB_DISABLE;
> + *cs++ = MI_NOOP;
> intel_ring_advance(rq, cs);
>
> return 0;
> @@ -2104,7 +2107,7 @@ static void gen8_emit_breadcrumb(struct i915_request *request, u32 *cs)
> cs = gen8_emit_ggtt_write(cs, request->global_seqno,
> intel_hws_seqno_address(request->engine));
> *cs++ = MI_USER_INTERRUPT;
> - *cs++ = MI_NOOP;
> + *cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
> request->tail = intel_ring_offset(request, cs);
> assert_ring_tail_valid(request->ring, request->tail);
>
> @@ -2120,7 +2123,7 @@ static void gen8_emit_breadcrumb_rcs(struct i915_request *request, u32 *cs)
> cs = gen8_emit_ggtt_write_rcs(cs, request->global_seqno,
> intel_hws_seqno_address(request->engine));
> *cs++ = MI_USER_INTERRUPT;
> - *cs++ = MI_NOOP;
> + *cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
> request->tail = intel_ring_offset(request, cs);
> assert_ring_tail_valid(request->ring, request->tail);
>
>
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next prev parent reply other threads:[~2018-05-03 20:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-03 19:54 [PATCH] drm/i915/execlists: Drop preemption arbitrations points along the ring Chris Wilson
2018-05-03 20:00 ` Michel Thierry [this message]
2018-05-03 20:10 ` Lionel Landwerlin
2018-05-03 20:38 ` ✓ Fi.CI.BAT: success for " Patchwork
2018-05-04 0:31 ` ✓ Fi.CI.IGT: " Patchwork
2018-05-04 6:33 ` Chris Wilson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=07c4673e-bbd0-b4ee-35df-c2220af60fd4@intel.com \
--to=michel.thierry@intel.com \
--cc=chris@chris-wilson.co.uk \
--cc=intel-gfx@lists.freedesktop.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.