On 06/15/2017 01:43 AM, Noam Camus wrote:
> From: Noam Camus <noamca at mellanox.com>
>
> We add ability for all cores at NPS SoC to control the number of cycles
> HW thread can execute before it is replace with another eligible
> HW thread within the same core. The replacement is done by the
> HW scheduler.
>
> Signed-off-by: Noam Camus <noamca at mellanox.com>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 9 ++++
> arch/arc/plat-eznps/mtm.c | 46 ++++++++++++++++++++++-
> 2 files changed, 53 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 15f79c2..5b551f7 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2693,6 +2693,15 @@
> If the dependencies are under your control, you can
> turn on cpu0_hotplug.
>
> + nps_mtm_hs_ctr= [KNL,ARC]
> + This parameter sets the maximum duration, in
> + cycles, each HW thread of the CTOP can run
> + without interruptions, before HW switches it.
> + The actual maximum duration is 16 times this
> + parameter's value.
> + Format: integer between 1 and 255
> + Default: 255
> +
> nptcg= [IA-64] Override max number of concurrent global TLB
> purges which is reported from either PAL_VM_SUMMARY or
> SAL PALO.
> diff --git a/arch/arc/plat-eznps/mtm.c b/arch/arc/plat-eznps/mtm.c
> index dcbf8f6..9c78ad6 100644
> --- a/arch/arc/plat-eznps/mtm.c
> +++ b/arch/arc/plat-eznps/mtm.c
> @@ -21,10 +21,13 @@
> #include <plat/mtm.h>
> #include <plat/smp.h>
>
> -#define MT_CTRL_HS_CNT 0xFF
> +#define MT_HS_CNT_MIN 0x01
> +#define MT_HS_CNT_MAX 0xFF
> #define MT_CTRL_ST_CNT 0xF
> #define NPS_NUM_HW_THREADS 0x10
>
> +static int mtm_hs_ctr = MT_HS_CNT_MAX;
> +
> #ifdef CONFIG_EZNPS_MEM_ERROR_ALIGN
> int do_memory_error(unsigned long address, struct pt_regs *regs)
> {
> @@ -127,7 +130,7 @@ void mtm_enable_core(unsigned int cpu)
> /* Enable HW schedule, stall counter, mtm */
> mt_ctrl.value = 0;
> mt_ctrl.hsen = 1;
> - mt_ctrl.hs_cnt = MT_CTRL_HS_CNT;
> + mt_ctrl.hs_cnt = mtm_hs_ctr;
> mt_ctrl.mten = 1;
> write_aux_reg(CTOP_AUX_MT_CTRL, mt_ctrl.value);
>
> @@ -138,3 +141,42 @@ void mtm_enable_core(unsigned int cpu)
> */
> cpu_relax();
> }
> +
> +/* Handle an out of bounds mtm hs counter value */
> +static void __init handle_mtm_hs_ctr_out_of_bounds_error(uint8_t val)
> +{
> + pr_err("** The value must be in range [%d,%d] (inclusive)\n",
> + MT_HS_CNT_MIN, MT_HS_CNT_MAX);
> +
> + mtm_hs_ctr = val;
This error handling doesn't make sense to me - if the value is not in range, why
bother setting it at all. I'll fix it up locally.
> +}
> +
> +/* Verify and set the value of the mtm hs counter */
> +static int __init set_mtm_hs_ctr(char *ctr_str)
> +{
> + int ret;
> + long hs_ctr;
> +
> + ret = kstrtol(ctr_str, 0, &hs_ctr);
> + if (ret) {
> + pr_err("** Out of range mtm_hs_ctr, using default value %d\n",
> + MT_HS_CNT_MAX);
> + mtm_hs_ctr = MT_HS_CNT_MAX;
> + return -EINVAL;
> + }
> +
> + if (hs_ctr > MT_HS_CNT_MAX) {
> + handle_mtm_hs_ctr_out_of_bounds_error(MT_HS_CNT_MAX);
> + return -EDOM;
> + }
> +
> + if (hs_ctr < MT_HS_CNT_MIN) {
> + handle_mtm_hs_ctr_out_of_bounds_error(MT_HS_CNT_MIN);
> + return -EDOM;
> + }
> +
> + mtm_hs_ctr = hs_ctr;
> +
> + return 0;
> +}
> +early_param("nps_mtm_hs_ctr", set_mtm_hs_ctr);
>
