On 05/15/2014 09:17 PM, Eric Blake wrote:
As shown in 'man virsh' about schedinfo:
Note: The cpu_shares parameter has a valid value range of 0-262144; This note documents historical kernel limits; if the kernel has changed,
On 05/15/2014 03:39 AM, Dongsheng Yang wrote: this may be out of date.
...
+++ b/src/qemu/qemu_driver.c @@ -112,6 +112,8 @@ VIR_LOG_INIT("qemu.qemu_driver"); #define QEMU_SCHED_MAX_PERIOD 1000000LL #define QEMU_SCHED_MIN_QUOTA 1000LL #define QEMU_SCHED_MAX_QUOTA 18446744073709551LL +#define QEMU_SCHED_MIN_SHARES 2LL +#define QEMU_SCHED_MAX_SHARES 262144LL I'm a bit reluctant to add these numbers - if the kernel ever changes its range again (which HAS happened for some cgroup tunables), then we are needlessly preventing use of the newer range.
Yes, I hate these numbers too. But the range is defined in kernel/sched/sched.h #define MIN_SHARES (1UL << 1) #define MAX_SHARES (1UL << 18) and used in scheduler. shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES)); So we can not access it out from kernel. As I found there was some numbers for period and quota here, I added the shares number here.