Date: Thu, 19 Mar 2009 23:06:57 +0100 From: Max Laier <max@love2party.net> To: freebsd-current@freebsd.org, barney_cordoba@yahoo.com Cc: Julian Elischer <julian@elischer.org>, current@freebsd.org Subject: Re: Is there a delay which yields? Message-ID: <200903192306.57780.max@love2party.net> In-Reply-To: <258770.46329.qm@web63908.mail.re1.yahoo.com> References: <258770.46329.qm@web63908.mail.re1.yahoo.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thursday 19 March 2009 23:02:49 Barney Cordoba wrote: > --- On Thu, 3/19/09, John Baldwin <jhb@freebsd.org> wrote: > > From: John Baldwin <jhb@freebsd.org> > > Subject: Re: Is there a delay which yields? > > To: freebsd-current@freebsd.org, barney_cordoba@yahoo.com > > Cc: "Julian Elischer" <julian@elischer.org>, current@freebsd.org > > Date: Thursday, March 19, 2009, 11:23 AM > > > > On Sunday 15 March 2009 2:43:18 pm Barney Cordoba wrote: > > > --- On Sun, 3/15/09, Julian Elischer > > > > <julian@elischer.org> wrote: > > > > From: Julian Elischer <julian@elischer.org> > > > > Subject: Re: Is there a delay which yields? > > > > To: barney_cordoba@yahoo.com > > > > Cc: current@freebsd.org > > > > Date: Sunday, March 15, 2009, 1:16 PM > > > > > > > > Barney Cordoba wrote: > > > > > I'd expect DELAY to yield till timeout > > > > but a task > > > > > > with a delay loop just > > > > > > > > > runs to 100% usage. Is there a function > > > > which can > > > > > > yield exectution for > > > > > > > > > a set amount of time (without having to use > > > > a timer)? > > > > > > DELAY is designe for use early in the boot when > > > > thre are no > > > > > > timers. > > > > it is only occasionally used for cases during > > > > normal > > > > > > operation. > > > > > > > > how would a thread know how long it has been away > > > > if no > > > > > > timer is used? > > > > > > I guess I mean a sleep. > > > > > > Also, this is a kernel driver. I have a device > > > which requires a toggle with a 10ms delay between > > > > pulses. I hate to > > > > > tie up the cpu for 10ms with a delay. Sort of like the > > > > following: > > > write_pulse(); > > > delay(10000); > > > write_pulse(); > > > > Use pause(9). > > timo is in hz? So 1/1000th of a second by default? tvtohz() (see time.h) will help you figure out how many ticks you need for a given timeval. > Also, I notice that hz is 1000 but get 2000 ints/second per > cpu. Why is it twice hz? That I don't know. -- /"\ Best regards, | mlaier@freebsd.org \ / Max Laier | ICQ #67774661 X http://pf4freebsd.love2party.net/ | mlaier@EFnet / \ ASCII Ribbon Campaign | Against HTML Mail and News
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200903192306.57780.max>