* using system serial drivers
@ David
` Samuel Thibault
0 siblings, 1 reply; 3+ messages in thread
From: David @ UTC (permalink / raw)
To: speakup
I have not measured the performance of doing bulk vs one char transfers.
Have any of you bothered to read the code in the driver you are calling
and see what overhead is imposed on entry/exit? It is quite abit.
Some synths already have their own catch up handlers, so it would be quite
easy to write a new do_catchup that used the new serial
i/o and each synth could call the new one when appropriate.
With respect to isa cards, I wrote the dec pc driver for the
old long isa card so I am aware of the fact that
all drivers do not use serial ports.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: using system serial drivers
using system serial drivers David
@ ` Samuel Thibault
` Samuel Thibault
0 siblings, 1 reply; 3+ messages in thread
From: Samuel Thibault @ UTC (permalink / raw)
To: Speakup is a screen review system for Linux.
Hello,
David, on Sat 19 Nov 2016 11:28:34 -0500, wrote:
> Have any of you bothered to read the code in the driver you are calling
> and see what overhead is imposed on entry/exit? It is quite abit.
That's still extremely slow compared to the actual time spent by
hardware to send the bytes over the wire. Really, nowadays we have
billions of instructions per seconds with all kinds of hardware
predictions to make things fast. The whole kernel has moved to making
things object-oriented to make it more modular etc., speakup can really
afford the same.
> Some synths already have their own catch up handlers, so it would be quite
> easy to write a new do_catchup that used the new serial
> i/o and each synth could call the new one when appropriate.
That'd bring more complexity that needed.
Really, what is costly nowadays is human time to write & read code, not
hardware time.
Samuel
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: using system serial drivers
` Samuel Thibault
@ ` Samuel Thibault
0 siblings, 0 replies; 3+ messages in thread
From: Samuel Thibault @ UTC (permalink / raw)
To: Speakup is a screen review system for Linux.
Samuel Thibault, on Sat 19 Nov 2016 22:47:09 +0100, wrote:
> David, on Sat 19 Nov 2016 11:28:34 -0500, wrote:
> > Have any of you bothered to read the code in the driver you are calling
> > and see what overhead is imposed on entry/exit? It is quite abit.
>
> That's still extremely slow compared to the actual time spent by
> hardware to send the bytes over the wire.
Oops, sorry, I meant "low" instead of "slow".
Samuel
^ permalink raw reply [flat|nested] 3+ messages in thread
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