Re: Free software
On Saturday 22 July 2017 07:25:27 rhkramer@gmail.com wrote:
> On Friday, July 21, 2017 11:49:04 PM Gene Heskett wrote:
> > Not hardly, the vesa standard, and the cards that support it cannot
> > do more that 15 frames a second, at nowhere near the resolution we
> > need, which these days is 1920P @ 60 fps. You can buy $90 monitors
> > at wallies that can do that today. I just did 90 days ago.
>
> Why do you need 1920P @ 60 fps? I thought you were referring to the
> needs of your machine shop, but, clearly, the next paragraph
> contradicts that...
>
Why so? I get the 1920P ok, and thats nice with ageing, diabetic
eyesight. Its the fps that suffers in this case. Watching htop while
its running the machine for very long, and theres plenty of cpu to
spare. The slow fps is clearly the fault of the usb2 pinhole all the
data that is not gpio related, has to get thru before it gets to the
hdmi interface and the monitor.
hdparm pretty much detects that, here is a terabyte drive plugged into
the usb plugs:
pi@picncsheldon:~ $ sudo hdparm -tT /dev/sda3
/dev/sda3:
Timing cached reads: 866 MB in 2.00 seconds = 433.15 MB/sec
Timing buffered disk reads: 78 MB in 3.01 seconds = 25.94 MB/sec
Note the nearly 20x slower reads when it has to go thru the usb2 sized
pinhole. The sd card fares even worse but throws an error:
pi@picncsheldon:~ $ sudo hdparm -tT /dev/mmcblk0p1
/dev/mmcblk0p1:
Timing cached reads: BLKFLSBUF failed: Operation not permitted
824 MB in 2.00 seconds = 411.42 MB/sec
BLKFLSBUF failed: Operation not permitted
Timing buffered disk reads: 40 MB in 1.92 seconds = 20.87 MB/sec
BLKFLSBUF failed: Operation not permitted
I want to see those results from a rock64.. I'll expect something more
like this:
root@coyote:~# hdparm -tT /dev/sda1
/dev/sda1:
Timing cached reads: 3330 MB in 2.00 seconds = 1664.90 MB/sec
Timing buffered disk reads: 534 MB in 3.01 seconds = 177.48 MB/sec
About 8.5x faster.
> > Define accelerated Ric. That 1920P @ 60 fps is nominally twice as
> > fast as the human eye can discern. I can be quite happy at 30fps,
> > interlaced, and I do not have a machine that cannot do at least
> > that, except an r-pi 3b, and I'm waiting to see if there are any
> > show stoppers in the 4Gb of ram you get with a rock64, which ships
> > with an even faster cpu, and claims no usb2 speed i/o bottleneck
> > which is currently killing the pi on my bigger lathe. The pi's
> > video is maybe 7 fps, slow enough to be a bother, but it runs the
> > machine with only an occasional stumble for 4 or 5 milliseconds. It
> > has not functionally damaged a workpiece yet. (knock knock)
I put the swap on the r-pi out to a hard drive, so the sd card might last
a little longer. But it made no difference in apt's speed doing major
updates since both paths have to go thru that usb2 pinhole. The rock64
claims to eliminate that, so I'll be most carefully watching their forum
in the weeks after it ships.
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
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