Gh0st
/
linux
mirror of https://github.com/torvalds/linux.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

arm_mpam: Consider overflow in bandwidth counter state 

Use the overflow status bit to track overflow on each bandwidth counter
read and add the counter size to the correction when overflow is detected.

This assumes that only a single overflow has occurred since the last read
of the counter. Overflow interrupts, on hardware that supports them could
be used to remove this limitation.

Cc: Zeng Heng <zengheng4@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Zeng Heng <zengheng4@huawei.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com>
Tested-by: Gavin Shan <gshan@redhat.com>
Tested-by: Zeng Heng <zengheng4@huawei.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Ben Horgan 2025-11-19 12:22:58 +00:00 committed by Catalin Marinas
parent 41e8a14950
commit b353637932
2 changed files with 24 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
drivers/resctrl/mpam_devices.c
View File

@ -985,11 +985,18 @@ static void write_msmon_ctl_flt_vals(struct mon_read *m, u32 ctl_val,
}
}
static u64 mpam_msmon_overflow_val(enum mpam_device_features type)
{
/* TODO: scaling, and long counters */
return BIT_ULL(hweight_long(MSMON___VALUE));
}
static void __ris_msmon_read(void *arg)
{
u64 now;
bool nrdy = false;
bool config_mismatch;
bool overflow;
struct mon_read *m = arg;
struct mon_cfg *ctx = m->ctx;
struct mpam_msc_ris *ris = m->ris;
@ -1011,13 +1018,20 @@ static void __ris_msmon_read(void *arg)
* This saves waiting for 'nrdy' on subsequent reads.
*/
read_msmon_ctl_flt_vals(m, &cur_ctl, &cur_flt);
overflow = cur_ctl & MSMON_CFG_x_CTL_OFLOW_STATUS;
clean_msmon_ctl_val(&cur_ctl);
gen_msmon_ctl_flt_vals(m, &ctl_val, &flt_val);
config_mismatch = cur_flt != flt_val ||
cur_ctl != (ctl_val | MSMON_CFG_x_CTL_EN);
if (config_mismatch)
if (config_mismatch) {
write_msmon_ctl_flt_vals(m, ctl_val, flt_val);
overflow = false;
} else if (overflow) {
mpam_write_monsel_reg(msc, CFG_MBWU_CTL,
cur_ctl & ~MSMON_CFG_x_CTL_OFLOW_STATUS);
}
switch (m->type) {
case mpam_feat_msmon_csu:
@ -1037,7 +1051,13 @@ static void __ris_msmon_read(void *arg)
mbwu_state = &ris->mbwu_state[ctx->mon];
/* Include bandwidth consumed before the last hardware reset */
if (overflow)
mbwu_state->correction += mpam_msmon_overflow_val(m->type);
/*
* Include bandwidth consumed before the last hardware reset and
* a counter size increment for each overflow.
*/
now += mbwu_state->correction;
break;
default:

3
drivers/resctrl/mpam_internal.h
View File

@ -211,7 +211,8 @@ struct msmon_mbwu_state {
struct mon_cfg cfg;
/*
* The value to add to the new reading to account for power management.
* The value to add to the new reading to account for power management,
* and overflow.
*/
u64 correction;