Re: [ql-developers] Massive amount of job state transitions and re-scheduling

[Peter Graf]

Hi,

late continuation of this old thread. Two issues were discussed back then:

(1) A principal shortcoming of QDOS/SMS, that does not allow a highspeed 
multitasking TCP/IP implementation with an interrupt driven structure.

(2) A problem in QLwIP that occured only when an extremely high number of 
scheduler calls was made.

The good news: Problem (1) has been solved, thanks to an improvement for 
QDOS Classic written by Richard Zidlicky. Only few lines of code, but with 
great effect. It has allowed me to make the lowest driver level 
interrupt-triggered, without the latency problem when interacting with 
jobs. I plan more intense testing. Later on, the modification shall be 
discussed with Mark Swift.

Problem (2) also seems to be solved, as a side-effect of the other 
modification. Since the cause of the problem never was exactly found, I'm 
not sure wether this is just luck. But I have transfered several 100 MB of 
data over the network this evening and the wellknown "hanging" of the HTTPD 
job at full speed has not yet appeared again, so there's hope.

Kudos to Richard!

All the best
Peter
Just by the way, I never was a big fan of the Qubide IDE driver, but I must 
admit that it is more intelligent than the SMSQ/E driver. While the latter 
one needed to restrict buffer size for acceptable speed, Qubide can deal 
with huge buffers, without the "crawling slaveblock" effect. (Helpful for 
the HTTP server.)