Misleading benchmarks?

[philipturner]

The benchmarks only include inference latency, but the actual latency is much larger. For example, they say it takes 18 seconds on the 32c M1 Max, which I have validated. However, there's an additional 22-second latency before that where it says Sampling.... I pulled it up in Activity Monitor, and here's what's happening:

• Loading resources and creating pipeline - 2 seconds, because I've already run the model several times
• Sampling... - 99% CPU, ~0% GPU, which means one CPU core utilized through this entire step (not multi-core), 22 seconds
• Step 50 of 50 [mean: 0.99, median: 1.56, last 1.55] step/sec - ~0% CPU, 88% GPU, which means the actual model is running, 18 seconds
• Total time: 40 seconds

Is anyone else getting these wierd results? Is it the same, or much larger than 22 seconds? I don't know whether it's because I used the Swift CLI instead of the Python CLI. I cannot get the Python CLI to work: https://github.com/apple/ml-stable-diffusion/issues/43#issuecomment-1344970169.

[philipturner]

Variations in execution time based on batch size:

BATCH_SIZE={1,2,3,4,5}
swift run StableDiffusionSample "a photo of an astronaut riding a horse on mars" \
--resource-path ../mlpackages/Resources --seed 93 --output-path ../outputs \
--compute-units cpuAndGPU --disable-safety --image-count=BATCH_SIZE

Batch Size	Loading Resources	Sampling	Inference (50 steps)	Total
1	4 sec	17 sec	16 sec	37 sec
2	4 sec	20 sec	32 sec	56 sec
3	4 sec	20 sec	49 sec	73 sec
4	4 sec	20 sec	66 sec	90 sec
5	4 sec	21 sec	81 sec	106 sec

Measured manually with the iPhone Timer app, so results may deviate from actual values by ~2 seconds.

[philipturner]

I guess the benchmarks aren't entirely wrong. The throughput for batched images is 16 seconds/image - probably smaller than Apple's 18 sec because I disabled the NSFW filtering model.

However, Apple should warn users about the ~20 second static overhead. This would be important for people making one-off images where the 40-second feedback loop is their bottleneck, not absolute batched throughput.

[littleowl]

Curious what your setting is for the compute units. Try setting it to .all @Option(help: "Compute units to load model with {all,cpuOnly,cpuAndGPU,cpuAndNeuralEngine}") var computeUnits: ComputeUnits = .all I've not noticed the large sampling every startup - until I changed it to cpuAndGPU and then I can reproduce your findings. - referring to the CLI. With setting to .all, it starts up rather quickly just a second or two. The behavior might be different with different settings based on device and the memory capabilities. I would imagine, if you were building an application, that you could account for the setup time. Maple/Native Diffusion implementation has a similar initial startup penalty. I've not fully tested the recommended settings with ANE with this on devices yet, but maybe it can be faster on device with that setup? My guess is with such large models there is a cost loading all the weights to the GPU.

[philipturner]

referring to the CLI. With setting to .all, it starts up rather quickly just a second or two.

It worked! I had compiled the attention implementation to be GPU-friendly (ORIGINAL), although I did see ANECompilerService compiling something for the neural engine. Perhaps the original sampling pass occurred on the ANE, and the inference pass occurred on the GPU (with 70% utilization).

Latencies: 4 sec, 1 sec, 19 sec. I'll switch back to v1.5 and provide an updated table of latencies, along with performance when optimizing attention for the ANE. Meanwhile, here's the various power consumption metrics during the sampling state with .all:

Here

Stage	Timestamp (s)	CPU (mW)	GPU (mW)	ANE (mW)
Load	-0.3	2595	35	0
Load	-0.2	2815	0	0
Load	-0.1	4279	18	0
Sample	0.0	3685	53	0
Sample	0.1	2923	9	0
Sample	0.2	2397	9	0
Sample	0.3	2447	9	0
Sample	0.4	2569	9	0
Sample	0.5	3383	1563	0
Sample	0.6	3611	88	283
Sample	0.7	2622	5227	441
Sample	0.8	1818	5393	3195
Sample	0.9	1717	1903	3859
Sample	1.0	2417	5144	759
Inference	1.1	2531	14464	573
Inference	1.2	440	11207	1549
Inference	1.3	217	1224	4255
Inference	1.4	508	13588	2359
Inference	1.5	1439	18315	1324

Sampling is too quick to 100% prove whether it's actually utilizing the ANE, or just late to report that it started inferencing.

And here's the metrics with .cpuAndGPU (~36 watts during inference):

Here

Stage	Timestamp (s)	CPU (mW)	GPU (mW)	ANE (mW)
Sample	-0.5	1428	9	0
Sample	-0.4	1416	18	0
Sample	-0.3	2390	26	0
Sample	-0.2	1650	14378	0
Sample	-0.1	1982	40245	0
Inference	0	1156	35068	0
Inference	0.1	1105	33366	0
Inference	0.2	839	40909	0
Inference	0.3	1343	27957	0
Inference	0.4	503	38959	0

[philipturner]

Note that if you try to re-run the command for generating a CoreML model, it will actually silently fail. You have to purge the mlpackages directory. I did not know this when switching between SPLIT_EINSUM and ORIGINAL previously.

BATCH_SIZE={1,2,3,4,5}
swift run StableDiffusionSample "a photo of an astronaut riding a horse on mars" \
--resource-path ../mlpackages/Resources --seed 93 --output-path ../outputs \
--compute-units all --disable-safety --image-count=BATCH_SIZE

With attention set to ORIGINAL (~15 watts during inference):

Here

Batch Size	Loading Resources	Sampling	Inference (50 steps)	Total
1	3	1	19	24
2	3	2	39	44
3	4	2	60	65
4	3	3	79	85
5	3	3	-	-
10	3	6	-	-
20	3	9	-	-
40	3	17	-	-

This seems to have marginally slower batched throughput (20 sec vs 16 sec), but about half the power consumption (15 W vs 36 W). Overall, it seems better than .cpuAndGPU. The GPU:ANE performance ratio stays the same on M1 Ultra, so these should be the best settings on all Apple silicon Macs.

With attention set to SPLIT_EINSUM (~13 watts during inference):

Here

Batch Size	Loading Resources	Sampling	Inference (50 steps)	Total
1	5	1	22	29
2	5	2	45	52
3	5	2	68	75

With attention set to SPLIT_EINSUM and only .cpuAndNeuralEngine: (~3 watts during inference)

Here

Batch Size	Loading Resources	Sampling	Inference (50 steps)	Total
1	4	1	39	44
1	4	2	77	83
1	4	3	116	122

[philipturner]

I've predicted the likely (actual) fastest implementation on each M1 model, and adjusted the numbers to match CLI latencies.

Device	--compute-unit	--attention-implementation	Latency (seconds)
Mac Studio (M1 Ultra, 64-core GPU)	ALL	ORIGINAL	9 -> 14
Mac Studio (M1 Ultra, 48-core GPU)	ALL	ORIGINAL	13 -> 18
MacBook Pro (M1 Max, 32-core GPU)	ALL	ORIGINAL	18 -> 24
MacBook Pro (M1 Max, 24-core GPU)	ALL	ORIGINAL	20 -> 26
MacBook Pro (M1 Pro, 16-core GPU)	ALL	SPLIT_EINSUM	26 -> 30
MacBook Pro (M1)	CPU_AND_NE	SPLIT_EINSUM	35 -> 39

Regarding battery life on M1 Max, there's a tradeoff between latency and power efficiency. You may want to use the neural engine when on battery. I assumed 3 W during load and sample, except for 1.5 W (sampling, .cpuAndGPU).

Compute Units	Attention	Runtime	Energy (J)	Inferences/Charge	Battery Life
.cpuAndGPU	ORIGINAL	37	614	~420	4 hours
.all	ORIGINAL	24	297	~870	6 hours
.all	SPLIT_EINSUM	29	304	~850	7 hours
.cpuAndNeuralEngine	SPLIT_EINSUM	44	132	~1960	24 hours

Assuming a 100 watt-hour battery at 90% health, or 324,000 joules. The battery will be drained from 90% to 10%, a typical real-world scenario.

[hirakujira]

The benchmark is still misleading. They said they could generate an image with M1 Ultra 48-core GPU within 13 seconds. And they didn't even use the swift package and neural engine!

The executed program is python_coreml_stable_diffusion.pipeline for macOS devices and a minimal Swift test app built on the StableDiffusion Swift package for iOS and iPadOS devices.

[rovo79]

Stage Timestamp (s) CPU (mW) GPU (mW) ANE (mW)

How do you obtain these detailed mW readings of the process running?

[philipturner]

sudo powermetrics —sample_rate 100

[rovo79]

Wow! I recall trying to use something like that a couple years ago but didn’t seem to exist on Macs. Was this recently re-added...

On Dec 20, 2022, at 8:33 AM, Philip Turner @.***> wrote:

powermetrics