search for: hyperthreading_allow

...P): APIC ID: 0 cpu1 (AP): APIC ID: 1 ioapic0: Changing APIC ID to 2 ioapic0 <Version 2.0> irqs 0-23 on motherboard ioapic1 <Version 2.0> irqs 24-47 on motherboard machdep.cpu_idle_hlt: 1 machdep.hlt_cpus: 0 machdep.hlt_logical_cpus: 0 machdep.logical_cpus_mask: 2 If I flip machdep.hyperthreading_allowed sysctl, I still can see processes scheduled to both logical CPUs, yet, if I check IRQ status in the systat -vm, the CPU1 is not getting any timer interrupts, while CPU0 gets twice the normal amount. I wonder if something is broken - I would expect no processes to be scheduled to the CPU1. ma...

...de channel which > exploits the L2 cache -- this is harder due to the larger size, > lower > bandwidth, and greater associativity -- and prohibiting shared L2 > caches turns Intel Core Duo processors into Intel Core Solo > processors. > > As before, the 'machdep.hyperthreading_allowed' sysctl will allow > even > the L1 data cache to be shared. I do not pretend to understand the background, but from your description it sounds like performance on Core Duo machines will be bad unless this change is made, or the potentially dangerous sysctl is active. If that...

...bed in <URL:http://www.freebsd.org/handbook/kernelconfig.html> and reboot the system. NOTE: For users that are certain that their environment is not affected by this vulnerability, such as single-user systems, Hyper-Threading Technology may be re-enabled by setting the tunable "machdep.hyperthreading_allowed". VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - ------------------------------------------------------------------------- RELENG_4 sr...

...bed in <URL:http://www.freebsd.org/handbook/kernelconfig.html> and reboot the system. NOTE: For users that are certain that their environment is not affected by this vulnerability, such as single-user systems, Hyper-Threading Technology may be re-enabled by setting the tunable "machdep.hyperthreading_allowed". VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - ------------------------------------------------------------------------- RELENG_4 sr...

...bed in <URL:http://www.freebsd.org/handbook/kernelconfig.html> and reboot the system. NOTE: For users that are certain that their environment is not affected by this vulnerability, such as single-user systems, Hyper-Threading Technology may be re-enabled by setting the tunable "machdep.hyperthreading_allowed". VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - ------------------------------------------------------------------------- RELENG_4 sr...

...bed in <URL:http://www.freebsd.org/handbook/kernelconfig.html> and reboot the system. NOTE: For users that are certain that their environment is not affected by this vulnerability, such as single-user systems, Hyper-Threading Technology may be re-enabled by setting the tunable "machdep.hyperthreading_allowed". VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - ------------------------------------------------------------------------- RELENG_4 sr...