Add INTEL_IDLE to list of problematic config options
PATCH 1/1 Add INTEL_IDLE to list of problematic config options
See TROUBLESHOOTING for explanation.
Signed-off-by Jan Kiszka <[email protected]>
--- TROUBLESHOOTING | 4 ++++ scripts/Kconfig.frag | 9 +++++---- 2 files changed, 9 insertions(+), 4 deletions(-)
TROUBLESHOOTING +4 -0
@@ -57,6 +57,10 @@ sleep states, increasing latency in ways dependent upon both the BIOS's ACPI tables and code. You may be able to suppress the sleeping with 'idle=poll' boot-arg, test to find out +INTEL_IDLE: Just like ACPI_PROCESSOR, this idle driver sends the CPU +into deep C states, also causing huge latencies because the APIC timer +that Xenomai uses may not fire anymore. + Summarizing, the latencies incurred here are dependent upon CPU, BIOS, and motherboard; ie they're hard to predict, so we are conservative. Feel free to test on your platform, (xeno-test runs testsuite/latency
scripts/Kconfig.frag +5 -4
@@ -1,10 +1,11 @@ menu "Real-time sub-system" -comment "WARNING! You enabled APM, CPU Frequency scaling or ACPI 'processor'" - depends on APM || CPU_FREQ || ACPI_PROCESSOR -comment "option. These options are known to cause troubles with Xenomai." - depends on APM || CPU_FREQ || ACPI_PROCESSOR +if APM || CPU_FREQ || ACPI_PROCESSOR || INTEL_IDLE +comment "WARNING! You enabled APM, CPU Frequency scaling, ACPI 'processor'" +comment "or Intel cpuidle option. These options are known to cause troubles" +comment "with Xenomai, disable them." +endif comment "NOTE: Xenomai conflicts with PC speaker support." depends on !X86_TSC && X86 && INPUT_PCSPKR
Signature · 1 line
1.7.1
Quoted 1 line · Jan Kiszka
See TROUBLESHOOTING for explanation.
Ok. Please update the wiki too.
Signature · 1 line
Gilles.
Quoted 5 lines · Gilles Chanteperdrix
Quoted 1 line · Jan Kiszka
See TROUBLESHOOTING for explanation.
Ok. Please update the wiki too.
Done.
Jan
Signature · 2 lines
Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux
Quoted 7 lines · Jan Kiszka
Quoted 4 lines · Gilles Chanteperdrix
Quoted 1 line · Jan Kiszka
See TROUBLESHOOTING for explanation.
Ok. Please update the wiki too.
Done.
I think we should also copy it to the x86 configuration page:
http://www.xenomai.org/index.php/Configuring_x86_kernels
And I wonder in fact if this information should be duplicated or if the FAQ should not point to this page.
Signature · 1 line
Gilles.