Re: [PATCH 9/9] sched/psi: add PSI_IRQ to track IRQ/SOFTIRQ pressure

Peter Zijlstra
2022-07-27T16:07:45Z

On Thu, Jul 21, 2022 at 12:04:39PM +0800, Chengming Zhou wrote:
> diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h
> index c124f7d186d0..195f123b1cd1 100644
> --- a/include/linux/psi_types.h
> +++ b/include/linux/psi_types.h
> @@ -47,7 +47,8 @@ enum psi_res {
> PSI_IO,
> PSI_MEM,
> PSI_CPU,
> - NR_PSI_RESOURCES = 3,
> + PSI_IRQ,
> + NR_PSI_RESOURCES = 4,
> };
>
> /*
> @@ -63,9 +64,11 @@ enum psi_states {
> PSI_MEM_FULL,
> PSI_CPU_SOME,
> PSI_CPU_FULL,
> + PSI_IRQ_SOME,
> + PSI_IRQ_FULL,
> /* Only per-CPU, to weigh the CPU in the global average: */
> PSI_NONIDLE,
> - NR_PSI_STATES = 7,
> + NR_PSI_STATES = 9,
> };
>
> enum psi_aggregators {

$ pahole -EC psi_group_cpu defconfig-build/kernel/sched/build_utility.o
struct psi_group_cpu {
/* typedef seqcount_t */ struct seqcount {
unsigned int sequence; /* 0 4 */
} seq __attribute__((__aligned__(64))); /* 0 4 */
unsigned int tasks[5]; /* 4 20 */
/* typedef u32 -> __u32 */ unsigned int state_mask; /* 24 4 */
/* typedef u32 -> __u32 */ unsigned int times[7]; /* 28 28 */
/* typedef u64 -> __u64 */ long long unsigned int state_start; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
/* typedef u32 -> __u32 */ unsigned int times_prev[2][7] __attribute__((__aligned__(64))); /* 64 56 */

/* size: 128, cachelines: 2, members: 6 */
/* padding: 8 */
/* forced alignments: 2 */
} __attribute__((__aligned__(64)));

$ pahole -EC psi_group_cpu defconfig-build/kernel/sched/build_utility.o
struct psi_group_cpu {
/* typedef seqcount_t */ struct seqcount {
unsigned int sequence; /* 0 4 */
} seq __attribute__((__aligned__(64))); /* 0 4 */
unsigned int tasks[5]; /* 4 20 */
/* typedef u32 -> __u32 */ unsigned int state_mask; /* 24 4 */
/* typedef u32 -> __u32 */ unsigned int times[9]; /* 28 36 */
/* --- cacheline 1 boundary (64 bytes) --- */
/* typedef u64 -> __u64 */ long long unsigned int state_start; /* 64 8 */

/* XXX 56 bytes hole, try to pack */

/* --- cacheline 2 boundary (128 bytes) --- */
/* typedef u32 -> __u32 */ unsigned int times_prev[2][9] __attribute__((__aligned__(64))); /* 128 72 */

/* size: 256, cachelines: 4, members: 6 */
/* sum members: 144, holes: 1, sum holes: 56 */
/* padding: 56 */
/* forced alignments: 2, forced holes: 1, sum forced holes: 56 */
} __attribute__((__aligned__(64)));

So yeah, I think not.