On Tuesday, November 28, 2017 6:15:59 PM PST Ian Romanick wrote: > On 11/28/2017 04:13 PM, Kenneth Graunke wrote: > > Once we reach the intended size of the buffer (BATCH_SZ or STATE_SZ), we > > try and flush. If we're not allowed to flush, we resort to growing the > > buffer so that there's space for the data we need to emit. > > > > We accidentally got the threshold wrong. The first non-wrappable call > > beyond (e.g.) STATE_SZ would grow the buffer to floor(1.5 * STATE_SZ), > > The next call would see we were beyond STATE_SZ and think we needed to > > grow a second time - when the buffer was already large enough. > > > > We still want to flush when we hit STATE_SZ, but for growing, we should > > use the actual size of the buffer as the threshold. This way, we only > > grow when actually necessary. > > > > Fixes: 2dfc119f22f257082ab0 "i965: Grow the batch/state buffers if we need > > space and can't flush." > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103101 > > --- > > src/mesa/drivers/dri/i965/intel_batchbuffer.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/src/mesa/drivers/dri/i965/intel_batchbuffer.c > > b/src/mesa/drivers/dri/i965/intel_batchbuffer.c > > index 216073129ba..1d0292b4b80 100644 > > --- a/src/mesa/drivers/dri/i965/intel_batchbuffer.c > > +++ b/src/mesa/drivers/dri/i965/intel_batchbuffer.c > > @@ -373,7 +373,7 @@ intel_batchbuffer_require_space(struct brw_context > > *brw, GLuint sz, > > if (batch_used + sz >= BATCH_SZ) { > > Why not just change this test to >= batch->bo->size?
We want to flush when we reach BATCH_SZ (the intended flush point). If we reach that point but are in the middle of something which makes makes it unsafe to flush (no_wrap), then we keep going, growing the BO as necessary. When growing, we only want to grow if we exceed the actual buffer size. I'm not a huge fan of how this is structured, so if you have an idea for how to make it more obvious, I'm open to suggestions.
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