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

2005-03-14 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 interrupt

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 > >

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 assertion to

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

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 the

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

2005-03-08 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

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

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

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

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 the