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by jerrm
Thu Jun 28, 2018 1:52 pm
Forum: General discussion
Topic: Pi3 - USB boot
Replies: 52
Views: 23521

Re: Pi3 - USB boot

I notice my pi runs about 5 degrees hotter celsius when running over USB than off the microSD. Perhaps i need to run it off a powered hub to take the strain off the pi. Temp may be due to the fact the Pi is constantly at 10% CPU utilization when there is no SD card. A rather important detail none o...
by jerrm
Fri Jun 22, 2018 10:43 pm
Forum: Beginners
Topic: Raspberry pi 3 b and the industry
Replies: 18
Views: 1097

Re: Raspberry pi 3 b and the industry

I have also asked this question on reddit and someone said that for these kind of things, industries use devices such as cRIO from National Instruments, but RPI would be used as a prototyping instrument. That would be enough to justify my academic project to use RPi. For academic purposes, I don't ...
by jerrm
Wed Jun 13, 2018 4:39 pm
Forum: Troubleshooting
Topic: Raspberry Pi 3 B+ lockups
Replies: 464
Views: 56938

Re: Raspberry Pi 3 B+ lockups

I have a 3B+ tested by @PhilE which he confirmed has no RAM issues. Have you tried the 450 option? I don't think it's a matter of RAM not running at 500 but of timing/interaction issues with other subsystems. Pi3B+ is not an option for us until there is a pretty clear "we know the issue and here is...
by jerrm
Wed Jun 13, 2018 3:55 pm
Forum: General discussion
Topic: Raspberry Pi 3 Model B+ clusters
Replies: 35
Views: 5611

Re: Raspberry Pi 3 Model B+ clusters

A Pi would definitely be I/O bound. A Pi won't come close to 41MB/s with a straight "cp" command

I doubt it would be an exaggeration that it would take 5+ Pis all working in parallel just to average the output you'd get from a single x86 sub-$100 refurb PC.
by jerrm
Tue Jun 12, 2018 6:54 pm
Forum: Advanced users
Topic: Daisy chaining ethernet with raspberry pi.
Replies: 11
Views: 1469

Re: Daisy chaining ethernet with raspberry pi.

Anyone old enough to remember daisy chained networks (the good old days of 10base-2) will have plenty of stories about them going wrong - any break in the chain meant the whole segment went down (as it was no longer properly terminated) and you got lots of unhappy people. Finding the one connection...
by jerrm
Tue Jun 12, 2018 4:14 pm
Forum: Advanced users
Topic: Daisy chaining ethernet with raspberry pi.
Replies: 11
Views: 1469

Re: Daisy chaining ethernet with raspberry pi.

You could add a USB adapter to each Pi and bridge the interfaces, effectively daisy chaining. Pretty simple to do, but I wouldn't recommend it. If a pi in the middle is down/locked up/turned off, everything downstream would lose connectivity. Strategically adding some switches along the line so that...
by jerrm
Mon Jun 11, 2018 10:54 pm
Forum: Beginners
Topic: slow copy of files via rsync from Windows 10 to RPi
Replies: 2
Views: 379

Re: slow copy of files via rsync from Windows 10 to RPi

Testing on wired LAN I get about 11MB/s with large files and 8MB/s with a mix of large and small for Cygwin <--> RPi3.

The 11MB/s is about 90% of wire speed, and probably the best that can be expected.

Did you get a chance to test against something other than the Pi?
by jerrm
Sun Jun 10, 2018 5:40 am
Forum: Beginners
Topic: slow copy of files via rsync from Windows 10 to RPi
Replies: 2
Views: 379

Re: slow copy of files via rsync from Windows 10 to RPi

At LAN speeds the compression setting (z parameter) in the linked example for files copied FROM the pi does more harm than good, but should be no where near as bad as what you are seeing. I'm remote right now, but Cygwin to a Pi3B is running about 1.5MB/s (your 3MB file would take 2 seconds) over th...
by jerrm
Fri Jun 08, 2018 8:19 pm
Forum: Beginners
Topic: backup windows directories to RPi over the network
Replies: 5
Views: 457

Re: backup windows directories to RPi over the network

If win10 machines you have control over, bash for Windows (WSL) will do what you need.

If activating WSL isn't doable, Google "cygwin portable install" for a free option.
by jerrm
Thu Jun 07, 2018 6:29 pm
Forum: Troubleshooting
Topic: Boot from USB hangs with USB Hub
Replies: 4
Views: 607

Re: Boot from USB hangs with USB Hub

Bootcode.bin is just more robust boot code. The on chip storage for the soc firmware is very limited and they cannot squeeze in all they need to have a 100% reliable usb boot for all possible configurations. Another thing worth trying is a different usb hub that uses a different chipset. They are no...
by jerrm
Thu Jun 07, 2018 4:29 pm
Forum: Troubleshooting
Topic: Boot from USB hangs with USB Hub
Replies: 4
Views: 607

Re: Boot from USB hangs with USB Hub

Have you tried an SD card with ONLY the bootcode.bin file present?
by jerrm
Mon Jun 04, 2018 10:57 pm
Forum: Beginners
Topic: Creating a custom image
Replies: 3
Views: 3044

Re: Creating a custom image

This won't be possible. WSL does a pretty good job at userland jobs like compiling code, running a LAMP stack, etc. Unfortunately, manipulating block devices, creating partitions and mounting file systems is all outside of it's scope. WSL cannot directly mount an ext4 partition. All the kernel level...
by jerrm
Sat Jun 02, 2018 2:09 pm
Forum: Troubleshooting
Topic: High CPU usage when booting from USB
Replies: 35
Views: 5375

Re: High CPU usage when booting from USB

Has anyone written a simple sd slot control script... "sdslot on" and "sdslot off" would seem useful. PeterO Just cut and paste the code from the systemd script. The only thing to change is the "%n" value for the /var/run file - replace it with something like "$(basename $0)". Also - no problem ins...
by jerrm
Fri Jun 01, 2018 4:25 pm
Forum: Troubleshooting
Topic: High CPU usage when booting from USB
Replies: 35
Views: 5375

Re: High CPU usage when booting from USB

I updated the systemd hack for Jessie compatibility: https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=211912#p1321571. Also, looks like the sdtweak.dtbo changes have been merged and should available via rpi-update now. The sdtweak method is the better of the two. It hopefully will be good goi...
by jerrm
Thu May 31, 2018 6:34 pm
Forum: Troubleshooting
Topic: High CPU usage when booting from USB
Replies: 35
Views: 5375

Re: High CPU usage when booting from USB

Nice. However having system set to 'stop' such service and initialize card at shutdown right before poweroff is not very optimal. Hopefuly the worst case is that the shutdown will be a tiny bit slower. I would agree, but my Pi's are up for months at a time, the "one file" fix was my choice. I updat...
by jerrm
Wed May 30, 2018 2:00 pm
Forum: Troubleshooting
Topic: High CPU usage when booting from USB
Replies: 35
Views: 5375

Re: High CPU usage when booting from USB

Nice. However having system set to 'stop' such service and initialize card at shutdown right before poweroff is not very optimal. Hopefuly the worst case is that the shutdown will be a tiny bit slower. I would agree, but my Pi's are up for months at a time, the "one file" fix was my choice. Easy en...
by jerrm
Wed May 30, 2018 4:46 am
Forum: Troubleshooting
Topic: High CPU usage when booting from USB
Replies: 35
Views: 5375

Re: High CPU usage when booting from USB

Below is a crude systemd unit to unbind the driver if no card is present at boot. No doubt a lot more checks should be built in for differing configurations, but it suffices for my needs - simple one file fix I can make part of my standard config (assuming no issues come up with further testing). Te...
by jerrm
Mon May 28, 2018 7:22 pm
Forum: Troubleshooting
Topic: High CPU usage when booting from USB
Replies: 35
Views: 5375

Re: High CPU usage when booting from USB

USB Boot is nearly two years old and is now enabled by default on the 3B+. I doubt there are any grand revelations coming. The advantages and uses are self evident. A 10% hit to performance is more than modest. It essentially negates the the CPU improvement between the 3B and 3B+. It also has a smal...
by jerrm
Sun May 27, 2018 2:24 pm
Forum: Troubleshooting
Topic: High CPU usage when booting from USB
Replies: 35
Views: 5375

Re: High CPU usage when booting from USB

It's not logging, it's polling the sd slot to see it you've inserted an sd card. If you USB boot you can hot plug sd-cards but I believe the PI doesn't use a "card inserted" physical switch so the kernel has to poll the slot by trying to read the card. But it is an insane amount of CPU usage for su...
by jerrm
Fri May 25, 2018 7:32 pm
Forum: Beginners
Topic: cloning images
Replies: 5
Views: 467

Re: cloning images

For the Pi's where I want to keep a complete image backup for quick restore purposes I create a full baseline image stored on an NFS share acting as the backup server. To save space image can be a sparse file and/or stored file system that supports compression or de-duplication (zfs/btrfs/etc). For ...
by jerrm
Fri May 25, 2018 5:05 pm
Forum: Troubleshooting
Topic: New Pi b3+ - SD and HDD storage size issue
Replies: 32
Views: 2028

Re: New Pi b3+ - SD and HDD storage size issue

wow this updating process is so slow.. its way slower then on the SD.. even booting to the rpi gui interface was slow.. what could be the reason? If your going without any SD card at all, check your CPU usage. Without an SD card, Pi's waste cpu cycles, and not all top utilities make it obvious. See...
by jerrm
Fri May 25, 2018 3:57 pm
Forum: Troubleshooting
Topic: Segmentation Fault while running cpuburn a-53
Replies: 20
Views: 1441

Re: Segmentation Fault while running cpuburn a-53

try running multiple instances of memtester - I have overclocked my pi3+ and running a single instance repeatedly (memtester 100M 30) would not fail, but running a couple of instances would fail after a few passes. I backed off the sdram clock until it ran through several memtester instances withou...
by jerrm
Thu May 24, 2018 11:15 pm
Forum: Troubleshooting
Topic: New Pi b3+ - SD and HDD storage size issue
Replies: 32
Views: 2028

Re: New Pi b3+ - SD and HDD storage size issue

wow this updating process is so slow.. its way slower then on the SD.. even booting to the rpi gui interface was slow.. what could be the reason? If your going without any SD card at all, check your CPU usage. Without an SD card, Pi's waste cpu cycles, and not all top utilities make it obvious. See...
by jerrm
Thu May 24, 2018 11:10 pm
Forum: Troubleshooting
Topic: How to get rid of NOOBS
Replies: 8
Views: 862

Re: How to get rid of NOOBS

I can now boot exclusively from USB device using the "exported" Raspbian Stretch, and preserved my previous settings and packages. If your going without any SD card at all, check your CPU usage. Without an SD card, Pi's waste cpu cycles, and not all top utilities make it obvious. See https://www.ra...
by jerrm
Thu May 24, 2018 12:31 am
Forum: Graphics programming
Topic: MPEG2 patents expiring
Replies: 34
Views: 14528

Re: MPEG2 patents expiring

From your posts: You've been "burned" three times by the Foundation. Foundation products are underwhelming disappointments. The Foundation lies. The Foundation is price gouging. There is a lot of competition and more powerful options available. Why are you still here? I would walk away from any comp...

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