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UPSTREAM: perf/arm-cmn: Optimise DTC counter accesses

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In cases where we do know which DTC domain a node belongs to, we can
skip initialising or reading the global count in DTCs where we know
it won't change. The machinery to achieve that is mostly in place
already, so finish hooking it up by converting the vestigial domain
tracking to propagate suitable bitmaps all the way through to events.

Note that this does not allow allocating such an unused counter to a
different event on that DTC, because that is a flippin' nightmare.

Bug: 247832918
Change-Id: I6c17e17bf3279ead000abf11947cfa71a1e820bf
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/51d930fd945ef51c81f5889ccca055c302b0a1d0.1638530442.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
(cherry picked from commit 4f2c3872dde55090bf39e1f12a8517a32b6cd048)
Signed-off-by: Robin Peng <robinpeng@google.com>
This commit is contained in:
Robin Murphy
2021-12-03 11:44:57 +00:00
committed by Treehugger Robot
parent fb9091356e
commit 9a74f34abd
1 changed files with 12 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/perf/arm-cmn.c
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@@ -193,7 +193,7 @@ struct arm_cmn_node {
u8 occupid_count;
};
/* XP */
int dtc;
u8 dtc;
};
union {
u8 event[4];
@@ -968,14 +968,14 @@ static int arm_cmn_event_init(struct perf_event *event)
if (!hw->dn)
return -EINVAL;
for (dn = hw->dn; dn->type == type; dn++) {
if (!bynodeid) {
hw->num_dns++;
} else if (dn->id != nodeid) {
if (bynodeid && dn->id != nodeid) {
hw->dn++;
} else {
hw->num_dns = 1;
break;
continue;
}
hw->dtcs_used |= arm_cmn_node_to_xp(cmn, dn)->dtc;
hw->num_dns++;
if (bynodeid)
break;
}
if (!hw->num_dns) {
@@ -985,11 +985,6 @@ static int arm_cmn_event_init(struct perf_event *event)
nodeid, nid.x, nid.y, nid.port, nid.dev, type);
return -EINVAL;
}
/*
* By assuming events count in all DTC domains, we cunningly avoid
* needing to know anything about how XPs are assigned to domains.
*/
hw->dtcs_used = (1U << cmn->num_dtcs) - 1;
return arm_cmn_validate_group(event);
}
@@ -1311,6 +1306,7 @@ static int arm_cmn_init_dtcs(struct arm_cmn *cmn)
{
struct arm_cmn_node *dn, *xp;
int dtc_idx = 0;
u8 dtcs_present = (1 << cmn->num_dtcs) - 1;
cmn->dtc = devm_kcalloc(cmn->dev, cmn->num_dtcs, sizeof(cmn->dtc[0]), GFP_KERNEL);
if (!cmn->dtc)
@@ -1322,8 +1318,7 @@ static int arm_cmn_init_dtcs(struct arm_cmn *cmn)
for (dn = cmn->dns; dn->type; dn++) {
if (dn->type == CMN_TYPE_XP) {
if (dn->dtc < 0 && cmn->num_dtcs == 1)
dn->dtc = 0;
dn->dtc &= dtcs_present;
continue;
}
@@ -1333,8 +1328,8 @@ static int arm_cmn_init_dtcs(struct arm_cmn *cmn)
if (dn->type == CMN_TYPE_DTC) {
int err;
/* We do at least know that a DTC's XP must be in that DTC's domain */
if (xp->dtc < 0)
xp->dtc = dtc_idx;
if (xp->dtc == 0xf)
xp->dtc = 1 << dtc_idx;
err = arm_cmn_init_dtc(cmn, dn, dtc_idx++);
if (err)
return err;
@@ -1435,7 +1430,7 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset)
if (xp->id == (1 << 3))
cmn->mesh_x = xp->logid;
xp->dtc = -1;
xp->dtc = 0xf;
xp->dtm = dtm - cmn->dtms;
arm_cmn_init_dtm(dtm++, xp);