Raspberry Pi Forums

jahboater

Gavinmc42 wrote: ↑
Tue Dec 01, 2020 7:16 am
Why not try it yourself?

+1

It costs nothing to try and only a few minutes to deploy on a spare SD card.
In the unlikely event that you do have a problem, just put the old card back.

I have been using Raspberry Pi OS 64-bit since day one and never had a problem.

jahboater

I'm researching this right now, and will publish the information along with detailed instructions on As its name suggests cpuburn-a53 is best for the Pi's with Cortex-A53 cpu cores. It does run on Pi4 with its Cortex-A72 cores but doesn't produce such a rapid rise in temperature. On the original Pi...

jahboater

Dragontail281 wrote: ↑
Mon Nov 30, 2020 5:24 pm
If I overclock while using RetroPie, does it stay in place when I switch out the SD cards?

No, everything goes when you switch cards.

But then its only a 30 second edit to set the overclock on Raspberry Pi OS:

sudo nano /boot/config.txt

jahboater

Take a look at Linpack ...

Code: Select all

https://www.howtoforge.com/tutorial/hpl-high-performance-linpack-benchmark-raspberry-pi/

jahboater

Do you still need pthreads?
See section 7.26 in the ISO standard.

jahboater

Random write speed 113 IOPS (target 500) - FAIL 113 IOPS is appalling! See the minimum spec for A1 class cards (1500 IOPS) that you should be using for an OS system disk: https://www.sdcard.org/developers/overview/application/index.html The Sandisk A1 class cards are popular and my experience has b...

jahboater

Whilst I am quite happy with the 100MB/s Samsung cards I'm curious to know if the Pi 4 is be capable of using the extra speed provided by the more expensive Kingston Canvas Go Plus or Kingston Canvas React Plus. The Pi4 SD card speed is twice that of older models. I suggest you look for A1 class SD...

jahboater

pi3g wrote: ↑
Sat Nov 28, 2020 10:58 am
Yes, right - since they're based on the same SoC that seems reasonable

It hasn't got the fancy thermal management that the Pi3B+ (plus) has.

jahboater

pi3g wrote: ↑
Sat Nov 28, 2020 10:42 am
Do you have any experience with the Pi 2 v1.2?

No, sorry.

My guess is that it might approach Pi3 speeds.

jahboater

In my research it seems that the 3B+ is not particularly well suited for being overclocked, as it already has been clocked at it's limits. Do you have a different overclocking experience with the 3B+? I agree. I only ever managed a truly stable overclock of 25MHz :) The 40nm node size was at its li...

jahboater

To give the same output as my Rust and python here's a very naive C implementation. Over to you @jahboater to use your magic and speed it up dramatically. That seems pretty good, not sure it can be improved much, except perhaps by speeding up the little hash function - it seems to be all "user...

jahboater

Unless demonstrated otherwise I am inclined to think that the time spend loading a static executable is likely not much different from loading a dynamically linked executable and linking it up at run time. Yes - a simple test on my Pi4 showed no measurable difference. Might be different for the fir...

jahboater

but it is also important the size of the executable be less than the size of the data. Given the static linking used by Rust, Go and other new-kid programming languages, this could place a surprising limit on the speedup possible for counting characters. Not sure I understand that, but ... $ ls -l ...

jahboater

With these "higher level" languages, I never know whats going on under the hood! How is it reading the file? What block size is it using? What options were passed when the file was opened? With C on the other hand, what you see is what you get. The library functions open/mmap/lseek etc dir...

jahboater

That C code is *very* fast though. I doubt the Rust can be stripped down to that - even just mapping bytes as indices to a Vec. I will see what it does. In python there isn't much difference as list is already doing all kinds of mapping, so might as well just use a dict. I suspect much of the speed...

jahboater

jalih wrote: ↑
Fri Nov 27, 2020 12:07 pm
Remember, Python needs to track Unicode code points and C using char can just process bytes!

Yes, quite right.

jahboater

In C #include <stdio.h> #include <unistd.h> #include <sys/mman.h> #include <ctype.h> #include <fcntl.h> int main( void ) { int fd = open( "war_and_peace.txt", O_RDONLY ); size_t len = lseek( fd, 0, SEEK_END ); unsigned char *ptr = mmap( NULL, len, PROT_READ, MAP_PRIVATE, fd, 0 ); madvise( ...

jahboater

Perhaps might also use vcgencmd for the temperature, as they seem to differ slightly: pi@raspberrypi:~ $ vcgencmd measure_temp; cat /sys/class/thermal/thermal_zone0/temp temp=33.0'C 33589 pi@raspberrypi:~ $ vcgencmd measure_temp; cat /sys/class/thermal/thermal_zone0/temp temp=32.0'C 32128 pi@raspber...

jahboater

The ARM CPU cores in the M1 have a node size of 5nm, which is impressive.

jahboater

I think I did... Just to make it clear, every time I clicked on my root folder, located in my root directory, i.e., /root, I got a message stating "Permission denied," therefore, I went on google and found out that if I do Sudo Su, then input my password, which I somehow had created, that...

jahboater

pinoobs2 wrote: ↑
Thu Nov 26, 2020 3:07 pm
and I have created the empty file named "ssh" in the boot directory before installing the MicroSD card.

Has the "ssh" file been deleted?

jahboater

Having had time to get back to it, "Boot to Python" is correct, but I'm not convinced by its claims to be a "Python-based userspace". Seems to me to be a BusyBox userspace running Python 3.8 on top. Sounds like it. Adding "init=/usr/bin/python" to /boot/cmdline.txt boo...

jahboater

The only thing that's putting me off upgrading is that some articles mentioned the OS couldn't access the extra 4GB, thus making it redundant? Of course it can - google LPAE. See also the (beta) 64-bit Raspberry Pi OS: https://downloads.raspberrypi.org/raspios_arm64/images/ which obviously has no l...

jahboater

I guess the NOP instruction will use very little of the CPU's power. There are no register moves involved. No calculations. No conditions to check. The CPU will just sit there for one clock cycle doing nothing. Yes. I tried a simple loop: asm volatile ( "1: nop; b 1b" : ); It barely raise...

jahboater

itsjon wrote: ↑
Wed Nov 25, 2020 2:03 pm
Is is usable

Yes.

But it costs nothing to try ....

Search found 6488 matches

Re: Raspberry PI OS 64-bit Release Date

Re: Overclocking

Re: Overclocking RetroPie vs Raspberry Pi OS

Re: CPU testing

Re: multi threading in c

Re: SD card speed failing , on a brand new class 10 card

Re: SD card speed >100MB/s ?

Re: Overclocking

Re: Overclocking

Re: Overclocking

Re: Anyone using Rust on a PI ?

Re: Anyone using Rust on a PI ?

Re: Anyone using Rust on a PI ?

Re: Anyone using Rust on a PI ?

Re: Anyone using Rust on a PI ?

Re: Anyone using Rust on a PI ?

Re: Anyone using Rust on a PI ?

Re: CM3+ vcgencmd get_throttled and temperature limits

Re: A Birthday Present for Fido

Re: Access "ROOT" Folder

Re: Pi Zero W ssh "connection refused"

Re: snakeware: boot-to-Python linux distro

Re: How much RAM needed for a Plex Media Server on Pi4?

Re: Avoiding 100% CPU usage

Re: Latest PI 64