Re: about interrupt latency

2005-03-14 Thread zyphr
On Sat, 12 Mar 2005 10:01:43 -0700 (MST), Zwane Mwaikambo <[EMAIL PROTECTED]> wrote: > On Wed, 9 Mar 2005, Francesco Oppedisano wrote: > > > On Tue, 8 Mar 2005 12:09:58 -0700 (MST), Zwane Mwaikambo > > <[EMAIL PROTECTED]> wrote: > > > > > At some cpu frequency point on i386 the main cause of your

Re: about interrupt latency

2005-03-12 Thread Zwane Mwaikambo
On Wed, 9 Mar 2005, Francesco Oppedisano wrote: > On Tue, 8 Mar 2005 12:09:58 -0700 (MST), Zwane Mwaikambo > <[EMAIL PROTECTED]> wrote: > > > At some cpu frequency point on i386 the main cause of your interrupt > > service latency will be in the interrupt controller and how long from irq > > asse

Re: about interrupt latency

2005-03-09 Thread Francesco Oppedisano
On Tue, 8 Mar 2005 12:09:58 -0700 (MST), Zwane Mwaikambo <[EMAIL PROTECTED]> wrote: > At some cpu frequency point on i386 the main cause of your interrupt > service latency will be in the interrupt controller and how long from irq > assertion to the signal being recognised, resultant vector being

Re: about interrupt latency

2005-03-09 Thread Francesco Oppedisano
On Tue, 8 Mar 2005 14:03:21 -0500 (EST), linux-os > You can't measure interrupt latency that way even > though you may get the "correct" answer! Why do you think the technique is not valid? > Make a simple module that uses IRQ7, the printer-port > interrupt. Inside your ISR, you toggle one of th

Re: about interrupt latency

2005-03-08 Thread Zwane Mwaikambo
Hi Francesco, On Tue, 8 Mar 2005, Francesco Oppedisano wrote: > i'm trying to estimate the interrupt latency (time between hardware > interrrupt and the start of the ISR) of a linux kernel 2.4.29 and i used > a simple tecnique: inside the do_timer_interrupt i read the 8259 counter > to obtain

Re: about interrupt latency

2005-03-08 Thread linux-os
On Tue, 8 Mar 2005, Francesco Oppedisano wrote: Hi, i'm trying to estimate the interrupt latency (time between hardware interrrupt and the start of the ISR) of a linux kernel 2.4.29 and i used a simple tecnique: inside the do_timer_interrupt i read the 8259 counter to obtain the elapsed time. By th

about interrupt latency

2005-03-08 Thread Francesco Oppedisano
Hi, i'm trying to estimate the interrupt latency (time between hardware interrrupt and the start of the ISR) of a linux kernel 2.4.29 and i used a simple tecnique: inside the do_timer_interrupt i read the 8259 counter to obtain the elapsed time. By this mean i found a latency of about 6/7 microseco