User avatar
DavidS
Posts: 4247
Joined: Thu Dec 15, 2011 6:39 am
Location: USA
Contact: Website

Re: Assembler questions

Tue Jan 08, 2013 12:41 am

rurwin wrote:I'd interpret it differently. I'd say the process was I/O bound waiting for the SD 50% of the time. The fact that RiscOS gets more CPU %age indicates it is less efficient; maybe it has less intelligent, or just smaller, disk caches. The real measure of course, is how long the compilation takes.
I would agree, except that I run Linux from a custom RAM disk (I know this takes up some of the precious RAM), thus there is no bottle neck there. And I would have a hard time believing that that it takes as much time to copy the source from one part of ram to another as it does to compile.

Also the CPU usages that i mentioned were only during time that there was zero file system activity of any kind. Including the time spent on file system access would be unfair, as most of that time is dead time.

As a note when compiling on RISC OS I also use a ram disk, and I have compared compile times using the same version of GCC on both platforms configured as close to identically as possible and built from the same source tree. RISC OS is usually about twice as fast with the same compile options and identical source. Though I do admit that on RISC OS the disk access is not as efficient it is also a lot less used than with Linux, and any one looking for faster compile times would be using a RAM disk for both the source and output. This is another reason that an OS that does not waste RAM is so important.
RPi = The best ARM based RISC OS computer around
More than 95% of posts made from RISC OS on RPi 1B/1B+ computers. Most of the rest from RISC OS on RPi 2B/3B/3B+ computers

User avatar
DavidS
Posts: 4247
Joined: Thu Dec 15, 2011 6:39 am
Location: USA
Contact: Website

Re: Assembler questions

Tue Jan 08, 2013 12:58 am

I must apologize for get into an OS vs OS conversation here. I made the assumption that bare metal developers would use the most efficient tools that are available on the target platform. I like Linux, I Like RISC OS, I mostly like QNX, I Like FreeBSD. I know that each has its place and purpose. I have been attempting to develop my own ARM based OS, despite the issues involved therein (including the wish to support all ARM CPU's from the ARMv2 up to at least ARMv7(now that is a little bit of a headache), and possibly the ARMv8 (not sure with the strange way that it supports 32-bit code alongside 64-bit [looks like it may be harder than supporting both the 26-bit addressing only ARMs and the 32-bit addressing ARMS])
RPi = The best ARM based RISC OS computer around
More than 95% of posts made from RISC OS on RPi 1B/1B+ computers. Most of the rest from RISC OS on RPi 2B/3B/3B+ computers

User avatar
rurwin
Forum Moderator
Forum Moderator
Posts: 4258
Joined: Mon Jan 09, 2012 3:16 pm
Contact: Website

Re: Assembler questions

Tue Jan 08, 2013 7:31 am

Fair enough, me too. I just wanted to poke my head in to mention the init 1 thing.

As you were.

Return to “Bare metal, Assembly language”