data.md

Timings are represented as <extract> + <install> where:

• <extract> - time in seconds to untar/gunzip the tar or img.gz file, and store the resulting content
• <install> - time in seconds to copy SYSTEM, KERNEL and - for RPi - bootloader files to /flash

The RPi3+ <extract> and <install> times are highly variable when writing to /flash and /storage, which may suggest an issue with my RPi3+ hardware, SD card, or a kernel/driver bug (or some combination of all three). The total time to upgrade the RPi3+ via tar file can vary by as much as 80 seconds. We don't see this issue when extacting to tmpfs, but it is seen when installing to /flash, which might suggest a performance issue when writing to the SD card.

We currently use dd with bs=1M (and conv=fsync) to transfer data to /flash, I wonder if we can do better here - something for later.

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RPi1

• 310MB RAM available with gpu_mem=160
• /flash on 8GB SD Class2 SD card, /storage on 32GB USB memory stick
• tar 129MB, img.gz 549MB (uncompressed)

tar [without SD overclock]

Run#	tmpfs	/storage
1	4.34 + 20.63	26.29 + 21.64
2	4.33 + 19.76	27.32 + 19.73
3	4.32 + 19.69	26.39 + 19.62

tar [63MHz SD overclock]

Run#	tmpfs	/storage
1	4.65 + 19.50	27.43 + 18.51
2	4.35 + 18.76	26.33 + 20.41
3	4.65 + 20.33	28.53 + 19.06

img.gz [without SD overclock]

Run#	tmpfs	/storage
1	xxxxxxxxxxxx	63.52 + 23.64
2	xxxxxxxxxxx6	61.18 + 22.56
3	xxxxxxxxxxxx	60.15 + 22.81

img.gz [63MHz SD overclock]

Run#	tmpfs	/storage
1	xxxxxxxxxxxx	62.12 + 25.03
2	xxxxxxxxxxxx	62.25 + 24.08
3	xxxxxxxxxxxx	62.17 + 23.51

---

RPi3+

• 628MB RAM available with gpu_mem=320
• /flash & /storage on 32GB SD Class10 SD card
• No CPU overclock, force_turbo=0
• tar 128MB, img.gz 549MB (uncompressed)

tar [without SD overclock]

Run#	tmpfs	/storage
1	6.15 + 24.69	13.30 + 33.49
2	6.04 + 13.15	21.77 + 16.41
3	6.05 + 14.40	18.74 + 13.86

tar [100MHz overclock]

Run#	tmpfs	/storage
1	3.55 + 61.38	12.14 + 32.06
2	3.55 + 26.48	18.77 + 72.97
3	3.58 + 10.83	30.25 + 82.18

img.gz [without SD overclock]

Run#	tmpfs	/storage
1	10.98 + 12.57	66.54 + 43.82
2	11.01 + 15.52	37.49 + 29.98
3	11.00 + 32.51	41.94 + 24.92

img.gz [100MHz SD overclock]

Run#	tmpfs	/storage
1	8.95 + 12.90	30.52 + 49.01
2	9.02 + 13.50	29.98 + 29.04
3	8.95 + 15.74	26.42 + 29.50

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RPi4 (4GB)

• 3467MB RAM available
• /flash & /storage on SD Card (32GB SanDisk Extreme Class A1)
• No CPU overclock, force_turbo=0
• tar 126MB, img.gz 549MB (uncompressed)

tar

Run#	tmpfs	/storage
1	3.76 + 22.67	16.06 + 18.40
2	3.58 + 18.65	18.18 + 20.83
3	3.77 + 16.33	16.12 + 20.88

img.gz

Run#	tmpfs	/storage
1	9.36 + 16.07	54.99 + 21.01
2	9.35 + 16.14	54.63 + 20.76
3	9.36 + 13.60	52.63 + 18.09

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Skylake i5 NUC

• 7496MB RAM available
• /flash & /storage on 128GB NVMe
• tar 229MB, img.gz 549MB (uncompressed)

tar

Run#	tmpfs	/storage
1	0.69 + 5.02	2.07 + 4.91
2	0.73 + 4.89	2.54 + 5.25
3	0.70 + 4.85	2.09 + 5.00

img.gz

Run#	tmpfs	/storage
1	3.48 + 5.18	6.83 + 5.66
2	3.41 + 5.07	7.02 + 5.84
3	3.50 + 5.22	6.80 + 5.39

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Revo 3700 (Atom D525)

• 1735MB RAM available
• /flash & /storage on 160GB 2.5" HDD
• tar 229MB, img.gz 549MB (uncompressed)

tar

Run#	tmpfs	/storage
1	7.83 + 15.79	16.28 + 15.88
2	7.78 + 16.69	16.31 + 16.90
3	7.84 + 16.31	16.34 + 16.37

img.gz

Run#	tmpfs	/storage
1	11.78 + 16.45	29.34 + 16.53
2	11.79 + 16.33	29.44 + 19.66
3	11.78 + 17.31	29.43 + 17.15