Thanks! Gained a lot. Tom Mitchell <niftylinkern@xxxxxxxxxxxx> 于2022年12月8日周四 03:55写道： > > On Tue, Dec 6, 2022 at 8:17 PM Tony He <huangya90@xxxxxxxxx> wrote: > ... > > > > I'm studying the NIC driver with the book <<Understanding the linux > > network internals>>. This book uses 3com 3c59x NIC(3c59x.c) as an > > example. The driver is very old and few people discuss it, but it's a > > good place to start because it's simpler than many other drivers with > > advanced offload features. > > > > In the interrupt handler boomerang_rx(), I see it pre-allocate one new > ... > > > goto clear_complete; > Oh m a goto. > ... > > However, I see intel e1000 driver optimizes this. Intel doesn't > > pre-allocate one at a time. > .... > > I just want to know why this is faster. For all scenarios or some > > scenarios? Can someone analyse it rigorously? > > The first step is to examine the hardware data pages. > Most optimizations like this are shaped by hardware > > That said, buffer allocation in the kernel is slow(ish). > Any time there is sufficient ram to preallocate, do so in moderation. > ... > Interrupt latency. > It helps to have the hardware address a list of commands in a queue without > hardware intervention. > Networking: > a buffer window sent to the client allows that client to send data > without waiting on > a response and is unlikely to need to resend unless the network has loss. > > The networking buffer window strategy is a giant topic. > > Interrupt latency: that is another book and it depends on the hardware. Again > any hardware that can do useful work without interrupt servicing the better. > > Simple serial IO hardware drivers can be easier to research and analyze. > Again start with the hardware data sheets for UARTS and hardware and software > flow control over serial data links. > > Define: rigorously? Is this a homework assignment? No, this is NOT a homework assignment. Have worked a few years but my most areas were related to application instead of kernel and driver. _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
