X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=Documentation%2Fx86_64%2Fboot-options.txt;h=5c86ed6f0448a8e2378a4ba62d6cedecf236215c;hb=refs%2Fheads%2Fvserver;hp=b9e6be00cadfbc1f2e767076c467ccb6f6ad28e6;hpb=f7f1b0f1e2fbadeab12d24236000e778aa9b1ead;p=linux-2.6.git diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index b9e6be00c..5c86ed6f0 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -6,6 +6,18 @@ only the AMD64 specific ones are listed here. Machine check mce=off disable machine check + mce=bootlog Enable logging of machine checks left over from booting. + Disabled by default on AMD because some BIOS leave bogus ones. + If your BIOS doesn't do that it's a good idea to enable though + to make sure you log even machine check events that result + in a reboot. On Intel systems it is enabled by default. + mce=nobootlog + Disable boot machine check logging. + mce=tolerancelevel (number) + 0: always panic, 1: panic if deadlock possible, + 2: try to avoid panic, 3: never panic or exit (for testing) + default is 1 + Can be also set using sysfs which is preferable. nomce (for compatibility with i386): same as mce=off @@ -28,6 +40,22 @@ APICs no_timer_check Don't check the IO-APIC timer. This can work around problems with incorrect timer initialization on some boards. + apicmaintimer Run time keeping from the local APIC timer instead + of using the PIT/HPET interrupt for this. This is useful + when the PIT/HPET interrupts are unreliable. + + noapicmaintimer Don't do time keeping using the APIC timer. + Useful when this option was auto selected, but doesn't work. + + apicpmtimer + Do APIC timer calibration using the pmtimer. Implies + apicmaintimer. Useful when your PIT timer is totally + broken. + + disable_8254_timer / enable_8254_timer + Enable interrupt 0 timer routing over the 8254 in addition to over + the IO-APIC. The kernel tries to set a sensible default. + Early Console syntax: earlyprintk=vga @@ -47,7 +75,7 @@ Timing notsc Don't use the CPU time stamp counter to read the wall time. This can be used to work around timing problems on multiprocessor systems - with not properly synchronized CPUs. Only useful with a SMP kernel + with not properly synchronized CPUs. report_lost_ticks Report when timer interrupts are lost because some code turned off @@ -74,11 +102,14 @@ Idle loop event. This will make the CPUs eat a lot more power, but may be useful to get slightly better performance in multiprocessor benchmarks. It also makes some profiling using performance counters more accurate. + Please note that on systems with MONITOR/MWAIT support (like Intel EM64T + CPUs) this option has no performance advantage over the normal idle loop. + It may also interact badly with hyperthreading. Rebooting reboot=b[ios] | t[riple] | k[bd] [, [w]arm | [c]old] - bios Use the CPU reboto vector for warm reset + bios Use the CPU reboot vector for warm reset warm Don't set the cold reboot flag cold Set the cold reboot flag triple Force a triple fault (init) @@ -109,6 +140,9 @@ SMP cpumask=MASK only use cpus with bits set in mask + additional_cpus=NUM Allow NUM more CPUs for hotplug + (defaults are specified by the BIOS, see Documentation/x86_64/cpu-hotplug-spec) + NUMA numa=off Only set up a single NUMA node spanning all memory. @@ -117,6 +151,11 @@ NUMA numa=fake=X Fake X nodes and ignore NUMA setup of the actual machine. + numa=hotadd=percent + Only allow hotadd memory to preallocate page structures upto + percent of already available memory. + numa=hotadd=0 will disable hotadd memory. + ACPI acpi=off Don't enable ACPI @@ -144,7 +183,7 @@ PCI IOMMU iommu=[size][,noagp][,off][,force][,noforce][,leak][,memaper[=order]][,merge] - [,forcesac][,fullflush][,nomerge][,noaperture] + [,forcesac][,fullflush][,nomerge][,noaperture][,calgary] size set size of iommu (in bytes) noagp don't initialize the AGP driver and use full aperture. off don't use the IOMMU @@ -160,12 +199,39 @@ IOMMU allowed overwrite iommu off workarounds for specific chipsets. soft Use software bounce buffering (default for Intel machines) noaperture Don't touch the aperture for AGP. + allowdac Allow DMA >4GB + When off all DMA over >4GB is forced through an IOMMU or bounce + buffering. + nodac Forbid DMA >4GB + panic Always panic when IOMMU overflows + calgary Use the Calgary IOMMU if it is available swiotlb=pages[,force] pages Prereserve that many 128K pages for the software IO bounce buffering. force Force all IO through the software TLB. + calgary=[64k,128k,256k,512k,1M,2M,4M,8M] + calgary=[translate_empty_slots] + calgary=[disable=] + + 64k,...,8M - Set the size of each PCI slot's translation table + when using the Calgary IOMMU. This is the size of the translation + table itself in main memory. The smallest table, 64k, covers an IO + space of 32MB; the largest, 8MB table, can cover an IO space of + 4GB. Normally the kernel will make the right choice by itself. + + translate_empty_slots - Enable translation even on slots that have + no devices attached to them, in case a device will be hotplugged + in the future. + + disable= - Disable translation on a given PHB. For + example, the built-in graphics adapter resides on the first bridge + (PCI bus number 0); if translation (isolation) is enabled on this + bridge, X servers that access the hardware directly from user + space might stop working. Use this option if you have devices that + are accessed from userspace directly on some PCI host bridge. + Debugging oops=panic Always panic on oopses. Default is to just kill the process, @@ -175,9 +241,25 @@ Debugging kstack=N Print that many words from the kernel stack in oops dumps. -Misc + pagefaulttrace Dump all page faults. Only useful for extreme debugging + and will create a lot of output. - noreplacement Don't replace instructions with more appropiate ones - for the CPU. This may be useful on asymmetric MP systems - where some CPU have less capabilities than the others. + call_trace=[old|both|newfallback|new] + old: use old inexact backtracer + new: use new exact dwarf2 unwinder + both: print entries from both + newfallback: use new unwinder but fall back to old if it gets + stuck (default) + + call_trace=[old|both|newfallback|new] + old: use old inexact backtracer + new: use new exact dwarf2 unwinder + both: print entries from both + newfallback: use new unwinder but fall back to old if it gets + stuck (default) + +Misc + noreplacement Don't replace instructions with more appropriate ones + for the CPU. This may be useful on asymmetric MP systems + where some CPU have less capabilities than the others.