From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Xavier Wang" To: Subject: Re: [ECOS] nested interrupts Date: Thu, 18 Jan 2001 20:56:00 -0000 Message-id: <00e201c081d2$c303df20$6f2314ac@realtek.com.tw> References: <003b01c0811f$196395e0$6f2314ac@realtek.com.tw> <3A671913.9090209@caracal-tech.com> X-SW-Source: 2001-01/msg00330.html > > As I was explained here, a main purpose of a DSR is to avoid > scheduler's ready list manipulation from an interrupt. DSR mechanism > serializes access to the scheduler (to suspend or resume a thread, or > to send a message), thus completely avoiding disabling interrupts when > posting. Quite neat. There is a price to pay, however, since DSR > mechanism nearly doubles the time between posting interrupt and thread > resumption. Bearing this in mind, the only thing DSR absolutely has to > do is to notify the scheduler. All the rest ought to be done either in > an ISR or in a thread. > > Regards, > Sergei Slobodov Thanks for your explanation. But as I knew, ISRs should be as short as possible to reduce the time of masking interrupts and other non-critical stuff can be processed in DSRs. So I don't understand what the following means: "Bearing this in mind, the only thing DSR absolutely has to do is to notify the scheduler. All the rest ought to be done either in an ISR or in a thread."