From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philippe Gerum In-Reply-To: <4C0AB817.2070000@domain.hid> References: <4C07BA95.9080402@domain.hid> <1275759652.18250.178.camel@domain.hid> <4C0A9960.8040609@domain.hid> <4C0AA430.4000205@domain.hid> <4C0AB817.2070000@domain.hid> Content-Type: text/plain; charset="UTF-8" Date: Sat, 05 Jun 2010 23:09:51 +0200 Message-ID: <1275772191.18250.260.camel@domain.hid> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Adeos-main] [RFC][PATCH 2/2] x86: Add support for ipipe_get_irq_regs List-Id: General discussion about Adeos List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: adeos-main On Sat, 2010-06-05 at 22:48 +0200, Jan Kiszka wrote: > Gilles Chanteperdrix wrote: > > Jan Kiszka wrote: > >> Philippe Gerum wrote: > >>> On Thu, 2010-06-03 at 16:22 +0200, Jan Kiszka wrote: > >>>> From: Jan Kiszka > >>>> > >>>> Implement the x86 arch bits for ipipe_get_irq_regs support. This allows > >>>> to drop __ipipe_tick_regs and use the new service instead. > >>> I'm unsure whether this patch would actually replace __ipipe_tick_regs > >>> properly, particularly regarding how the profiling code works. > >> tick_regs are a "workaround", this approach appears to me way closer to > >> how native works. > > > > We do not want ipipe_tick_regs to work the way the native kernel works. > > We want to fool the kernel by passing it the value of the registers at > > the moment of the real timer tick so that its accounting works more or > > less reliably. When the kernel used the real registers it got the > > accounting wrong. > > Right, though current tick_regs approach is not accurate either: the > preempted task gets the full time slice accounted, neglecting the actual > schedule inside the preempting domain. > Indeed. This trade-off was made back in 2002. > > Jan > > _______________________________________________ > Adeos-main mailing list > Adeos-main@domain.hid > https://mail.gna.org/listinfo/adeos-main -- Philippe.