Hi Greg, > On Fri, Sep 01, 2006 at 02:33:42PM +0200, Jean Delvare wrote: > > Beyond the readability of the code, there are some performance issues > > to consider. For example I wonder how the code above interacts with the > > CPU cache, compared to 1-level-indexed callbacks, in the typical > > "sensors" scenario. I don't really have the time to investigate this, > > unfortunately. Switch/case is usually not recommended in performance > > terms, even though I'd expect gcc to optimize it relatively nicely if > > the "func" values are chosen wisely. > > I don't really think it maters at all. This code is not cache "hot" by > any means. It's doing something pretty infrequently, Could happen once every second or every other second, if the user has a GUI with sensors data (gkrellm, ksensors, xsensors...) I think it qualifies as "frequent". > and the i2c > protocol is _so_ slow it's not funny. These are not high-performance > things we are dealing with at all. Not all hardware monitoring chips are i2c-based. I agree that all hwmon drivers do quite a lot of I/O though, be it on the SMBus or ISA bus. But it's hardly a reason not to make the rest of the driver code smaller and faster if we can. > So please, don't worry about things like this in the i2c drivers, it's > not an issue. OK. -- Jean Delvare
