What is the difference between “Paint” and “Rasterize Paint” in Chrome dev-tools?
I've been reading about the critical rendering path in chrome here and here. My understanding from these resources is that the "Compositing" step happens off the main thread, and is dependant on the previous "Paint" step which produces the rasterized layers to be composited together.
However, when I look at what is happening during a single frame of a position animation in Chrome dev-tools I see this:
- It looks like "Compositing" is happening on the main thread, which is not what I understood from reading these resources.
- There is a paint step on the main thread before compositing, but then there is another "Rasterize Paint" step after compositing on a "Rasterizer Thread".
So what is the difference between "Paint" and "Rasterize Paint", and why does the rasterize paint step happen after compositing is already complete? And why does compositing appear to happen on the main thread in chrome dev-tools but the docs describe it as happening on a different thread?
google-chrome google-chrome-devtools web-performance asked Nov 15 '18 at 9:35
JohnJohn
9252818
add a comment |
I've been reading about the critical rendering path in chrome here and here. My understanding from these resources is that the "Compositing" step happens off the main thread, and is dependant on the previous "Paint" step which produces the rasterized layers to be composited together.
However, when I look at what is happening during a single frame of a position animation in Chrome dev-tools I see this:
- It looks like "Compositing" is happening on the main thread, which is not what I understood from reading these resources.
- There is a paint step on the main thread before compositing, but then there is another "Rasterize Paint" step after compositing on a "Rasterizer Thread".
So what is the difference between "Paint" and "Rasterize Paint", and why does the rasterize paint step happen after compositing is already complete? And why does compositing appear to happen on the main thread in chrome dev-tools but the docs describe it as happening on a different thread?
google-chrome google-chrome-devtools web-performance asked Nov 15 '18 at 9:35
JohnJohn
9252818
1) I think you should see a corresponding block in the GPU process under the Paint block, same for Compositing layers and the Compositor process; 2) I guess compositing layers is preparing the layers for the Compositor to compose; 3) Since Chrome uses Skia I guess "Paint" is the part of invoking Skia, while "Rasterize Paint" is the actual rasterizing done inside Skia. 4) I doubt a Chromium engineer would see this question so I think it's worth asking on crbug.com or chromium's IRC channel or some of their Google groups for developers.
– wOxxOm
Nov 16 '18 at 4:50
add a comment |
I've been reading about the critical rendering path in chrome here and here. My understanding from these resources is that the "Compositing" step happens off the main thread, and is dependant on the previous "Paint" step which produces the rasterized layers to be composited together.
However, when I look at what is happening during a single frame of a position animation in Chrome dev-tools I see this:
- It looks like "Compositing" is happening on the main thread, which is not what I understood from reading these resources.
- There is a paint step on the main thread before compositing, but then there is another "Rasterize Paint" step after compositing on a "Rasterizer Thread".
So what is the difference between "Paint" and "Rasterize Paint", and why does the rasterize paint step happen after compositing is already complete? And why does compositing appear to happen on the main thread in chrome dev-tools but the docs describe it as happening on a different thread?
google-chrome google-chrome-devtools web-performance asked Nov 15 '18 at 9:35
JohnJohn
9252818
I've been reading about the critical rendering path in chrome here and here. My understanding from these resources is that the "Compositing" step happens off the main thread, and is dependant on the previous "Paint" step which produces the rasterized layers to be composited together.
However, when I look at what is happening during a single frame of a position animation in Chrome dev-tools I see this:
- It looks like "Compositing" is happening on the main thread, which is not what I understood from reading these resources.
- There is a paint step on the main thread before compositing, but then there is another "Rasterize Paint" step after compositing on a "Rasterizer Thread".
So what is the difference between "Paint" and "Rasterize Paint", and why does the rasterize paint step happen after compositing is already complete? And why does compositing appear to happen on the main thread in chrome dev-tools but the docs describe it as happening on a different thread?
google-chrome google-chrome-devtools web-performance google-chrome google-chrome-devtools web-performance asked Nov 15 '18 at 9:35
JohnJohn
9252818
asked Nov 15 '18 at 9:35
JohnJohn
9252818
asked Nov 15 '18 at 9:35
JohnJohn
9252818
asked Nov 15 '18 at 9:35
JohnJohn
9252818
asked Nov 15 '18 at 9:35
JohnJohn
9252818
9252818
1) I think you should see a corresponding block in the GPU process under the Paint block, same for Compositing layers and the Compositor process; 2) I guess compositing layers is preparing the layers for the Compositor to compose; 3) Since Chrome uses Skia I guess "Paint" is the part of invoking Skia, while "Rasterize Paint" is the actual rasterizing done inside Skia. 4) I doubt a Chromium engineer would see this question so I think it's worth asking on crbug.com or chromium's IRC channel or some of their Google groups for developers.
– wOxxOm
Nov 16 '18 at 4:50
add a comment |
1) I think you should see a corresponding block in the GPU process under the Paint block, same for Compositing layers and the Compositor process; 2) I guess compositing layers is preparing the layers for the Compositor to compose; 3) Since Chrome uses Skia I guess "Paint" is the part of invoking Skia, while "Rasterize Paint" is the actual rasterizing done inside Skia. 4) I doubt a Chromium engineer would see this question so I think it's worth asking on crbug.com or chromium's IRC channel or some of their Google groups for developers.
– wOxxOm
Nov 16 '18 at 4:50
1) I think you should see a corresponding block in the GPU process under the Paint block, same for Compositing layers and the Compositor process; 2) I guess compositing layers is preparing the layers for the Compositor to compose; 3) Since Chrome uses Skia I guess "Paint" is the part of invoking Skia, while "Rasterize Paint" is the actual rasterizing done inside Skia. 4) I doubt a Chromium engineer would see this question so I think it's worth asking on crbug.com or chromium's IRC channel or some of their Google groups for developers.
– wOxxOm
Nov 16 '18 at 4:50
1) I think you should see a corresponding block in the GPU process under the Paint block, same for Compositing layers and the Compositor process; 2) I guess compositing layers is preparing the layers for the Compositor to compose; 3) Since Chrome uses Skia I guess "Paint" is the part of invoking Skia, while "Rasterize Paint" is the actual rasterizing done inside Skia. 4) I doubt a Chromium engineer would see this question so I think it's worth asking on crbug.com or chromium's IRC channel or some of their Google groups for developers.
– wOxxOm
Nov 16 '18 at 4:50
add a comment |
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1) I think you should see a corresponding block in the GPU process under the Paint block, same for Compositing layers and the Compositor process; 2) I guess compositing layers is preparing the layers for the Compositor to compose; 3) Since Chrome uses Skia I guess "Paint" is the part of invoking Skia, while "Rasterize Paint" is the actual rasterizing done inside Skia. 4) I doubt a Chromium engineer would see this question so I think it's worth asking on crbug.com or chromium's IRC channel or some of their Google groups for developers.
– wOxxOm
Nov 16 '18 at 4:50