Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753019AbZI0OkJ (ORCPT ); Sun, 27 Sep 2009 10:40:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752912AbZI0OkI (ORCPT ); Sun, 27 Sep 2009 10:40:08 -0400 Received: from ey-out-2122.google.com ([74.125.78.26]:38772 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752807AbZI0OkG (ORCPT ); Sun, 27 Sep 2009 10:40:06 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=WEcLMVewrQ1S38HVJKVbzdpeUZBBs0ifzw3Vdbt3fOSNNBrsp6VE48zAU1zHsgpVSv lXS3PQ1Px3GGkK5fBd3xaemVSFUSpVusHTvKK+nhMdlIoPws3lQmpBAiH39Wy6NciQ2O BMFmTpboCrzPWXdghjqj0/0FXMxAtPWinGh0w= Date: Sun, 27 Sep 2009 18:40:08 +0400 From: Cyrill Gorcunov To: Yinghai Lu , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] x86: add show_lapic= Message-ID: <20090927144008.GD4984@lenovo> References: <4ABF0DE0.1030400@kernel.org> <20090927080605.GA4984@lenovo> <4ABF2262.3090905@kernel.org> <20090927085406.GB4984@lenovo> <20090927102805.GC4984@lenovo> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090927102805.GC4984@lenovo> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6313 Lines: 201 [Cyrill Gorcunov - Sun, Sep 27, 2009 at 02:28:05PM +0400] | [Cyrill Gorcunov - Sun, Sep 27, 2009 at 12:54:06PM +0400] | | [Yinghai Lu - Sun, Sep 27, 2009 at 01:29:22AM -0700] | | | Cyrill Gorcunov wrote: | | | > [Yinghai Lu - Sun, Sep 27, 2009 at 12:01:52AM -0700] | | | > | | | | > | so could use that together with apci=debug to print less cpu apic. | | | > | | | | > | otherwise for system have more cpus will take a while | | | > | | | | > | also move apic_verbosity check to print_all_ICs | | | > | | | | > | Signed-off-by: Yinghai Lu | | | > | | | | > | --- | | | > | arch/x86/kernel/apic/io_apic.c | 42 ++++++++++++++++++++++++++--------------- | | | > | 1 file changed, 27 insertions(+), 15 deletions(-) | | | > ... | | | > | | | > Hi Yinghai, good idea! | | | > | | | > I've tuned your patch a bit together with changelog. | | | > | | | > 1) show_lapic=1 by default does change current kernel behaviour | | | > so it should be set to max cpu available. | | | | | | think about system with lots of cpu. but i still want to use apic=debug | | | | but you should not change current behaviour. starting with this change | | I'll get only first apic dump, so if I don;t know how many apics I have | | what the number I should pass? Does it mean I would need to | | pass say show_lapic=2, or 4, or 6 or whatever _all-the-time_ to be sure | | my Core2Duo prints all lapics? | | | | | | | | > 2) show_lapic contains the max number of lapics being printed | | | > so we need to count them instead of plain comparation with | | | > cpu number, as a result I've changed print_local_APICs. Or | | | > you meant _exactly_ cpuid number? In meaning like | | | > show_lapic=max_cpuid. Hmm? | | | > | | | your change anything about that. there is not gap between cpu id. | | | | you walk with for_each_online_cpu with is not the same | | as for_each_present_cpu. yes, at this stage we hardly get | | the situation when cpu initialized and then suddenly get | | offline status but anyway | | | | | | | | YH | | | | | -- Cyrill | | Also and your and my "update" (that named :-) missed the fact that get_option | may return without set argument at all, so num should be explicitly | initialized as well (in setup_show_lapic). | | -- Cyrill Yinghai, I've updated it to fix this nit. Convinced on for_each_online_cpu, since it's early stage indeed. But for show_lapic=1 by default -- this is plainly *wrong*. Now I put apic=debug and see only one apic dump regardless how many apics I have, so we should place limit explicitly. So here is an updated version. I don't know what is the best way would be to say that initial patch was yours and the idea as well. If you *agreed* on this patch -- you may either SOB it, Ack it, or take it without my SOB at all (ie do anything you like) -- I don't care much :) -- Cyrill --- [PATCH -tip] x86,apic: introduce show_lapic setup option In case if a system has a large number of cpus printing apics contents may consume a long time period. So to control it we introduce "show_lapic" setup option which allow us to limit the number of APICs being dumped. Example: apic=debug show_lapic=5 Also lift apic_verbosity checking upper that way so helper routines do not need to inspect it at all. Suggested-by: Yinghai Lu Signed-off-by: Cyrill Gorcunov --- arch/x86/kernel/apic/io_apic.c | 43 ++++++++++++++++++++++++++--------------- 1 file changed, 28 insertions(+), 15 deletions(-) Index: linux-2.6.git/arch/x86/kernel/apic/io_apic.c ===================================================================== --- linux-2.6.git.orig/arch/x86/kernel/apic/io_apic.c +++ linux-2.6.git/arch/x86/kernel/apic/io_apic.c @@ -1599,9 +1599,6 @@ __apicdebuginit(void) print_IO_APIC(void struct irq_desc *desc; unsigned int irq; - if (apic_verbosity == APIC_QUIET) - return; - printk(KERN_DEBUG "number of MP IRQ sources: %d.\n", mp_irq_entries); for (i = 0; i < nr_ioapics; i++) printk(KERN_DEBUG "number of IO-APIC #%d registers: %d.\n", @@ -1708,9 +1705,6 @@ __apicdebuginit(void) print_APIC_field(i { int i; - if (apic_verbosity == APIC_QUIET) - return; - printk(KERN_DEBUG); for (i = 0; i < 8; i++) @@ -1724,9 +1718,6 @@ __apicdebuginit(void) print_local_APIC(v unsigned int i, v, ver, maxlvt; u64 icr; - if (apic_verbosity == APIC_QUIET) - return; - printk(KERN_DEBUG "printing local APIC contents on CPU#%d/%d:\n", smp_processor_id(), hard_smp_processor_id()); v = apic_read(APIC_ID); @@ -1824,13 +1815,19 @@ __apicdebuginit(void) print_local_APIC(v printk("\n"); } -__apicdebuginit(void) print_all_local_APICs(void) +__apicdebuginit(void) print_local_APICs(int maxcpu) { int cpu; + if (!maxcpu) + return; + preempt_disable(); - for_each_online_cpu(cpu) + for_each_online_cpu(cpu) { + if (cpu >= maxcpu) + break; smp_call_function_single(cpu, print_local_APIC, NULL, 1); + } preempt_enable(); } @@ -1839,7 +1836,7 @@ __apicdebuginit(void) print_PIC(void) unsigned int v; unsigned long flags; - if (apic_verbosity == APIC_QUIET || !nr_legacy_irqs) + if (!nr_legacy_irqs) return; printk(KERN_DEBUG "\nprinting PIC contents\n"); @@ -1866,21 +1863,37 @@ __apicdebuginit(void) print_PIC(void) printk(KERN_DEBUG "... PIC ELCR: %04x\n", v); } -__apicdebuginit(int) print_all_ICs(void) +static int __initdata show_lapic = NR_CPUS; +static __init int setup_show_lapic(char *arg) { + int num = 0; + + get_option(&arg, &num); + if (num >= 0) + show_lapic = num; + + return 1; +} +__setup("show_lapic=", setup_show_lapic); + +__apicdebuginit(int) print_ICs(void) +{ + if (apic_verbosity == APIC_QUIET) + return 0; + print_PIC(); /* don't print out if apic is not there */ if (!cpu_has_apic && !apic_from_smp_config()) return 0; - print_all_local_APICs(); + print_local_APICs(show_lapic); print_IO_APIC(); return 0; } -fs_initcall(print_all_ICs); +fs_initcall(print_ICs); /* Where if anywhere is the i8259 connect in external int mode */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/