Messages in this thread | | | Date | Fri, 24 Sep 1999 17:45:55 +0200 | From | Henner Eisen <> | Subject | Re: 1000ms delay in networking stack or driver, new bug? |
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>>>>> "kuznet" == kuznet <kuznet@ms2.inr.ac.ru> writes:
kuznet> Hello! >> Just a final question: was the problem solely caused by the >> packet scheduler
kuznet> Yes. And it was utterly stupid.
>> in the device drivers that we nevertheless should try to find >> and fix?
kuznet> It is always useful 8)
And this particular bug was also useful because when hunting for it without beeing successful I detected at least several other ones :-)
kuznet> At least, looking at isdn, I see that it sometimes forgets kuznet> to mark NET_BH clearing tbusy. And even the fact that in kuznet> the cases when it does not forget it, clearing tbusy and kuznet> marking bh are made in different parts of code tells that kuznet> the driver assumes wrong things.
My first experiments when the problems where first observed was to analyse the isdn code and to insert mark_bh everywhere where tbusy was cleared. Analsysis also showed that mostly, tbusy was cleared correctly although that was not allways obvious from a first look at (but from more detailed study of) the code. As this did not change anything, those additinally inserted (but redundant) mark_bh where never commited to the offical source (only those that were really missing). IŽm fairly sure that now marking NET_BH is done correctly (although somewhat messily) as far as single link isdn connections are concerned (there might be possible problems with multilink, but as I cannot test these, I havenŽt done further work on this).
Henner
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