Hi, Sergey Semenov a écrit : > Does it influence on perfomance as much? Please, explain your point of > view. Thank you I don't think it has an influence on performances, but simply it's not the usual way of signaling an event to an userspace application. > I've implemented driver, which waits for some event from external > device. When this event comes, i should notify ASAP my user-space > application from kernel to achieve the fastest reaction. Now i am > using only signals and i don't know what i can do else. Can you advice > me something ? Thank you! If your application is waiting an event from a device, then it means that it called something like read(), write() or ioctl() which are then implemented in the kernel space driver. These functions can sleep in the kernel space driver until the event occurs. Then, they are unblocked and the userspace process can continue its execution. For example, your shell (/bin/bash) calls read() on a /dev/tty, and is blocked until an event occurs: here the event is the key press. It could be the reception of a network packet, or anything else. An other option is to go through the hotplug stuff (now called "uevent" if didn't miss the thing), but this is more for events that don't occur frequently, like device (un)plugging. Can you describe more precisely what your driver is for, what is the event, what does the application, etc. It's quite difficult to answer such a general question. Sincerly, Thomas -- Thomas Petazzoni thomas.petazzoni@xxxxxxxx -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
