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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 10:15:43 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 10:15:43 +0000
commit4a1c948bc688e5ab5e51d12d2f6dd6746e3ac2d9 (patch)
tree7ee50e6ccf13f75f02fd343cf90750cbd9950194 /arch/x86/kernel/cpu/resctrl
parentReleasing progress-linux version 6.1.82-1~progress6.99u1. (diff)
downloadlinux-4a1c948bc688e5ab5e51d12d2f6dd6746e3ac2d9.tar.xz
linux-4a1c948bc688e5ab5e51d12d2f6dd6746e3ac2d9.zip
Merging upstream version 6.1.85.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/kernel/cpu/resctrl')
-rw-r--r--arch/x86/kernel/cpu/resctrl/internal.h4
-rw-r--r--arch/x86/kernel/cpu/resctrl/monitor.c42
2 files changed, 10 insertions, 36 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 0b5c6c76f..4761d489a 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -281,14 +281,10 @@ struct rftype {
* struct mbm_state - status for each MBM counter in each domain
* @prev_bw_bytes: Previous bytes value read for bandwidth calculation
* @prev_bw: The most recent bandwidth in MBps
- * @delta_bw: Difference between the current and previous bandwidth
- * @delta_comp: Indicates whether to compute the delta_bw
*/
struct mbm_state {
u64 prev_bw_bytes;
u32 prev_bw;
- u32 delta_bw;
- bool delta_comp;
};
/**
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 77538abeb..b9adb7077 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -428,9 +428,6 @@ static void mbm_bw_count(u32 rmid, struct rmid_read *rr)
cur_bw = bytes / SZ_1M;
- if (m->delta_comp)
- m->delta_bw = abs(cur_bw - m->prev_bw);
- m->delta_comp = false;
m->prev_bw = cur_bw;
}
@@ -508,11 +505,11 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
{
u32 closid, rmid, cur_msr_val, new_msr_val;
struct mbm_state *pmbm_data, *cmbm_data;
- u32 cur_bw, delta_bw, user_bw;
struct rdt_resource *r_mba;
struct rdt_domain *dom_mba;
struct list_head *head;
struct rdtgroup *entry;
+ u32 cur_bw, user_bw;
if (!is_mbm_local_enabled())
return;
@@ -531,7 +528,6 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
cur_bw = pmbm_data->prev_bw;
user_bw = dom_mba->mbps_val[closid];
- delta_bw = pmbm_data->delta_bw;
/* MBA resource doesn't support CDP */
cur_msr_val = resctrl_arch_get_config(r_mba, dom_mba, closid, CDP_NONE);
@@ -543,49 +539,31 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
list_for_each_entry(entry, head, mon.crdtgrp_list) {
cmbm_data = &dom_mbm->mbm_local[entry->mon.rmid];
cur_bw += cmbm_data->prev_bw;
- delta_bw += cmbm_data->delta_bw;
}
/*
* Scale up/down the bandwidth linearly for the ctrl group. The
* bandwidth step is the bandwidth granularity specified by the
* hardware.
- *
- * The delta_bw is used when increasing the bandwidth so that we
- * dont alternately increase and decrease the control values
- * continuously.
- *
- * For ex: consider cur_bw = 90MBps, user_bw = 100MBps and if
- * bandwidth step is 20MBps(> user_bw - cur_bw), we would keep
- * switching between 90 and 110 continuously if we only check
- * cur_bw < user_bw.
+ * Always increase throttling if current bandwidth is above the
+ * target set by user.
+ * But avoid thrashing up and down on every poll by checking
+ * whether a decrease in throttling is likely to push the group
+ * back over target. E.g. if currently throttling to 30% of bandwidth
+ * on a system with 10% granularity steps, check whether moving to
+ * 40% would go past the limit by multiplying current bandwidth by
+ * "(30 + 10) / 30".
*/
if (cur_msr_val > r_mba->membw.min_bw && user_bw < cur_bw) {
new_msr_val = cur_msr_val - r_mba->membw.bw_gran;
} else if (cur_msr_val < MAX_MBA_BW &&
- (user_bw > (cur_bw + delta_bw))) {
+ (user_bw > (cur_bw * (cur_msr_val + r_mba->membw.min_bw) / cur_msr_val))) {
new_msr_val = cur_msr_val + r_mba->membw.bw_gran;
} else {
return;
}
resctrl_arch_update_one(r_mba, dom_mba, closid, CDP_NONE, new_msr_val);
-
- /*
- * Delta values are updated dynamically package wise for each
- * rdtgrp every time the throttle MSR changes value.
- *
- * This is because (1)the increase in bandwidth is not perfectly
- * linear and only "approximately" linear even when the hardware
- * says it is linear.(2)Also since MBA is a core specific
- * mechanism, the delta values vary based on number of cores used
- * by the rdtgrp.
- */
- pmbm_data->delta_comp = true;
- list_for_each_entry(entry, head, mon.crdtgrp_list) {
- cmbm_data = &dom_mbm->mbm_local[entry->mon.rmid];
- cmbm_data->delta_comp = true;
- }
}
static void mbm_update(struct rdt_resource *r, struct rdt_domain *d, int rmid)