<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Mon, Sep 5, 2016 at 7:39 PM, Michel Dänzer <span dir="ltr"><<a href="mailto:michel@daenzer.net" target="_blank">michel@daenzer.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">From: Michel Dänzer <<a href="mailto:michel.daenzer@amd.com">michel.daenzer@amd.com</a>><br>
<br>
This can make a significant difference for performance with some extreme<br>
test cases such as vblank_mode=0 glxgears.<br>
<br>
Fixes: 1e3218bc5ba2 ("loader/dri3: Overhaul dri3_update_num_back")<br>
Cc: "12.0 11.2" <<a href="mailto:mesa-stable@lists.freedesktop.org">mesa-stable@lists.<wbr>freedesktop.org</a>><br>
Bugzilla: <a href="https://bugs.freedesktop.org/show_bug.cgi?id=97549" rel="noreferrer" target="_blank">https://bugs.freedesktop.org/<wbr>show_bug.cgi?id=97549</a><br>
Signed-off-by: Michel Dänzer <<a href="mailto:michel.daenzer@amd.com">michel.daenzer@amd.com</a>><br>
---<br>
<br>
I could swear I tested vblank_mode=0 glxgears with my previous change<br>
and couldn't measure any difference, but I can now, so I must have<br>
messed up my previous testing somehow... Apologies for any inconvenience<br>
this caused.<br>
<br>
src/loader/loader_dri3_helper.<wbr>c | 4 +---<br>
1 file changed, 1 insertion(+), 3 deletions(-)<br>
<br>
diff --git a/src/loader/loader_dri3_<wbr>helper.c b/src/loader/loader_dri3_<wbr>helper.c<br>
index 86ae5ae..3ce0352 100644<br>
--- a/src/loader/loader_dri3_<wbr>helper.c<br>
+++ b/src/loader/loader_dri3_<wbr>helper.c<br>
@@ -70,10 +70,8 @@ dri3_update_num_back(struct loader_dri3_drawable *draw)<br>
{<br>
if (draw->flipping)<br>
draw->num_back = 3;<br>
- else if (draw->vtable->get_swap_<wbr>interval(draw) != 0)<br>
- draw->num_back = 2;<br>
else<br>
- draw->num_back = 1;<br>
+ draw->num_back = 2;<br></blockquote><div><br></div><div>With this change, the function is logically identical to the old function with the async flipping case removed. I'm still not sure why we aren't getting a stall with 3 butters in the swapinterval=0 flipping case, but if it doesn't have a perf impact, it must not be a problem.<br><br></div><div>Reviewed-by: Jason Ekstrand <<a href="mailto:jason@jlekstrand.net">jason@jlekstrand.net</a>><br><br></div><div>Thanks for digging into it to find the real problem. :-)<br><br></div><div>--Jason<br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
}<br>
<br>
void<br>
<span class="HOEnZb"><font color="#888888">--<br>
2.9.3<br>
<br>
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