Welcome! I'll guess answers without actually testing.
In all cases, actual 1-wire communication is the slowest part of the process. Each bit transmitted is 62usec The owshell approach requires a new process for every 1-wire call. Linux processes are supposed to fairly light but it's probably the slowest approach. And getting to that data in a C program isn't convenient. owfs should be pretty fast, the actual "filesystem" part of it does require a pass through the kernel for each transaction, but the fuse interface is pure subroutine calls. Getting to the data in C (or any language) is very convenient -- file access is natural. The owserver approach requires network communication. Again pretty fast. If you really want the lowest latency, use owcapi in your C program. There is no pass through the network or filesystem and the interface is simple. If other processes need to access the 1-wire data at the same time, you need owserver or the filesystem. If they need to access remotely, you need owserver. All the methods, including owcapi, can access owserver. All the methods are pretty fast and I'd choose the simplest approach for development. Alias should be pretty fast, it's just a binary table lookup from memory. Paul Alfille On Wed, Aug 10, 2011 at 4:11 AM, ekgnkb3d <[email protected]> wrote: > > Hello everybody, > I'm new to this forum and shortly want to introduce myself: > During my tests with 1-Wire for a hot-water controller, I used the Maxim > Public Domain Kit. But due to some limitations I try to switch to owfs now. > My biggest fear at owfs is a low performance causing high load at my CPU > which is with 400MHz and ARM9 very limited... I'm using an hardware I2C > channel /dev/i2c-0 with DS2482-100. The aim is to have a closed loop > controlling rate of max 250ms for 4 DS18B20 temp sensing plus DS2408 dac. > So > therefore my (newbie) questions: > > The convenience of all the different owfs client technologies is great > (thanks to the developers for this amazing piece of code!!!), assuming > there > is not much difference in adapting my C-coded application. Which one of the > following give the fastest access, creating the minimum CPU load: > > - owfs, accessing files in directories via fuse > - owshell, calling shell commands via local owserver > - owserver, adding code to my C-application acting as TCP client > > Or maybe it is not worth a discussion and all mentioned possibilities have > almost the same speed/load? > > Another questions: > Does using alias slowing down the access?? > > thanks a lot > Achim > -- > View this message in context: > http://old.nabble.com/different-access-performance-tp32230443p32230443.html > Sent from the OWFS - Dev mailing list archive at Nabble.com. > > > > ------------------------------------------------------------------------------ > uberSVN's rich system and user administration capabilities and model > configuration take the hassle out of deploying and managing Subversion and > the tools developers use with it. Learn more about uberSVN and get a free > download at: http://p.sf.net/sfu/wandisco-dev2dev > _______________________________________________ > Owfs-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/owfs-developers >
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