I'm a RISC OS user who is attempting to learn about one of the Linux distributions to try and get to grips with the Raspberry Pi GPIO. I'm using Wheezy-Raspbian that's modified to work with Ciseco shields and expansion boards on a Raspberry Pi model B, Rev 2 but it runs so slooow.. compared to RISC OS. Would Wheezy-Raspbian work any faster on the latest Raspberry Pi 2 with its quad core CPU?
Richard
You wait for the raspberry pi, model 3, a
A Hex core cpu.
Or better, but to have it in your hand, it's no more than a credit card size, with a chip the size of a small insect, and to think, it rates at least 1000 faster than an Apple II.
Only if:
1) your main application(s) is/are multithreaded (i.e. parallelized) or 2) you run several applications simultaneouslyThe corresponding cpu speeds are 700mhz and 900mhz (though both can be overclocked), so expect about a 9 to 7 speed increase on a typical single threaded application.
Just out of curiosity, what speed SD card are you running from? If it's a
4 instead of a 10, that's probably your bottleneck - unless you're running out of memory and paging quite a bit.
Or if you can benefit from the extra RAM.
Actually you will see a larger improvement that this. The ARMv7 is more efficient at processing instructions than the ARMv6 and you would probably get at least double the performance even if you disabled three of the cores on the ARMv7.
You don't need a multi-threaded app to see a greater improvement on four cores, as there is a fair bit of stuff going on in the background in Raspbian, so effectively three of the cores can handle that while your application gets a whole core just to itself.
Actual tests on non-multi-threaded apps seem to show a 4-6 times improvement in speed, while some multi-threaded applications show up to
32 times improvement.(I'm going on what various people have reported in tests, as I haven't got a Pi2 yet - I'm still very happy with my Pi1's)
Freespace 1.2GB on a 4GB, class 4 SDcard. Switched to a 4GB, class 10 card. I'll see if there's any difference.
It varies a bit between manufacturers - some older class 10 cards are awful. I quite like the Samsung orange cards or their older black class 6 cards. If you get a good card it can go up to 100x faster on random writes than a bad card.
Theo
On 13 Mar 2015 19:46:16 +0000 (GMT), Theo Markettos declaimed the following:
Since class 10 cards are rated based on streaming a single (video) file onto an empty card, while class 2/4/6 are rated on fragmented I/O (still cameras with deleted images), it is technically possible that a class 10 will rate much slower when doing fragmented/random I/O. A Class 10 could, hypothetically, be using an internal block size so large that multiple files are in one block and reading a file that starts near the end of the block requires scanning from the start of the block (all done in the card, of course).
Granted, by now I'd hope the major names have improved random access on class 10 cards.
--
Wulfraed Dennis Lee Bieber AF6VN
wlfraed@ix.netcom.com HTTP://wlfraed.home.netcom.com/
They do. Some cards are below 10KByte/s on 4KB random writes, others are better than 1MByte/s
Generally the major names aren't too bad, it's the rebranders (Transcend, Integral, Kingston, etc, who buy whatever flash is cheap this week) and the no-brand stuff you have to worry about. I think things have been improving, though I haven't tried rebrand/nobrand stuff recently.
Theo
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