From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 12 Feb 2002 19:33:17 +0100 From: Werner Almesberger To: benh@kernel.crashing.org Cc: linuxppc-dev@lists.linuxppc.org Subject: Re: performance monitor exceptions Message-ID: <20020212193317.F5079@almesberger.net> References: <20020211233730.E5079@almesberger.net> <20020212125502.32396@mailhost.mipsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20020212125502.32396@mailhost.mipsys.com>; from benh@kernel.crashing.org on Tue, Feb 12, 2002 at 01:55:01PM +0100 Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: benh@kernel.crashing.org wrote: > - I don't know how the perf. mon stuff works, but couldn't you > enter a condition were the CPU is continuously sending your the > pef monitor exception until you clear something else ? No, in a performance monitor exception, PMXE (PM exception enable) is cleared in MMCR0, and I need to set it explicitly to get another exception. The only performance event source that's enabled is the one using the timer base, so this gives me exceptions at 200 Hz, more if I want. > - I encountered a problem with the TAU stuff and the 7400 where > the CPU could actually get mixed up when getting both a normal > interrupt and a TAU exception and scew up itself (by taking both > exceptions and screwing up SRR0/1) Bingo ! That seems to be the one: http://www.mot.co.jp/SPS/html/lit/pdf/mpc7410pns_rev0.pdf #5: Description: Consecutive Performance Monitor, Decrementer, or Thermal Management Interrupts may become non-recoverable. Work-Around: Avoid enabling any combination of Performance Monitor, Decrementer, or Thermal Management Interrupts at the same time. Hmm, working around this will be tricky ... Thanks a lot ! - Werner -- _________________________________________________________________________ / Werner Almesberger, Lausanne, CH wa@almesberger.net / /_http://icawww.epfl.ch/almesberger/_____________________________________/ ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/