git: 87c4d6555b41 - main - hwpstate_amd: Use ipi instead of sched_bind + thread_lock
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Date: Fri, 16 Jan 2026 14:39:10 UTC
The branch main has been updated by aokblast:
URL: https://cgit.FreeBSD.org/src/commit/?id=87c4d6555b41a509ff1eeb24e2fa90f3f59483a7
commit 87c4d6555b41a509ff1eeb24e2fa90f3f59483a7
Author: ShengYi Hung <aokblast@FreeBSD.org>
AuthorDate: 2026-01-04 15:10:59 +0000
Commit: ShengYi Hung <aokblast@FreeBSD.org>
CommitDate: 2026-01-16 14:38:15 +0000
hwpstate_amd: Use ipi instead of sched_bind + thread_lock
Reviewed by: olce
Approved by: markj (mentor)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D54505
---
sys/x86/cpufreq/hwpstate_amd.c | 146 ++++++++++++++++++++++-------------------
1 file changed, 79 insertions(+), 67 deletions(-)
diff --git a/sys/x86/cpufreq/hwpstate_amd.c b/sys/x86/cpufreq/hwpstate_amd.c
index ce0e0f6dd47a..5676d8ce7dae 100644
--- a/sys/x86/cpufreq/hwpstate_amd.c
+++ b/sys/x86/cpufreq/hwpstate_amd.c
@@ -198,6 +198,26 @@ static device_method_t hwpstate_methods[] = {
{0, 0}
};
+struct amdhwp_dump_sysctl_handler_request {
+ uint64_t enable;
+ uint64_t caps;
+ uint64_t req;
+ int res;
+};
+
+static void
+amdhwp_dump_sysctl_handler_cb(void *args)
+{
+ struct amdhwp_dump_sysctl_handler_request *req =
+ (struct amdhwp_dump_sysctl_handler_request *)args;
+
+ req->res = rdmsr_safe(MSR_AMD_CPPC_ENABLE, &req->enable);
+ if (req->res == 0)
+ req->res = rdmsr_safe(MSR_AMD_CPPC_CAPS_1, &req->caps);
+ if (req->res == 0)
+ req->res = rdmsr_safe(MSR_AMD_CPPC_REQUEST, &req->req);
+}
+
static int
amdhwp_dump_sysctl_handler(SYSCTL_HANDLER_ARGS)
{
@@ -205,6 +225,7 @@ amdhwp_dump_sysctl_handler(SYSCTL_HANDLER_ARGS)
struct pcpu *pc;
struct sbuf *sb;
struct hwpstate_softc *sc;
+ struct amdhwp_dump_sysctl_handler_request request;
uint64_t data;
int ret;
@@ -217,20 +238,19 @@ amdhwp_dump_sysctl_handler(SYSCTL_HANDLER_ARGS)
sb = sbuf_new(NULL, NULL, 1024, SBUF_FIXEDLEN | SBUF_INCLUDENUL);
sbuf_putc(sb, '\n');
- thread_lock(curthread);
- sched_bind(curthread, pc->pc_cpuid);
- thread_unlock(curthread);
+ smp_rendezvous_cpu(pc->pc_cpuid, smp_no_rendezvous_barrier,
+ amdhwp_dump_sysctl_handler_cb, smp_no_rendezvous_barrier, &request);
+ ret = request.res;
+ if (ret)
+ goto out;
- rdmsr_safe(MSR_AMD_CPPC_ENABLE, &data);
+ data = request.enable;
sbuf_printf(sb, "CPU%d: HWP %sabled\n", pc->pc_cpuid,
((data & 1) ? "En" : "Dis"));
-
- if (data == 0) {
- ret = 0;
+ if (data == 0)
goto out;
- }
- rdmsr_safe(MSR_AMD_CPPC_CAPS_1, &data);
+ data = request.caps;
sbuf_printf(sb, "\tHighest Performance: %03ju\n",
BITS_VALUE(AMD_CPPC_CAPS_1_HIGH_PERF_BITS, data));
sbuf_printf(sb, "\tGuaranteed Performance: %03ju\n",
@@ -241,8 +261,7 @@ amdhwp_dump_sysctl_handler(SYSCTL_HANDLER_ARGS)
BITS_VALUE(AMD_CPPC_CAPS_1_LOW_PERF_BITS, data));
sbuf_putc(sb, '\n');
- rdmsr_safe(MSR_AMD_CPPC_REQUEST, &data);
-
+ data = request.req;
#define pkg_print(name, offset) \
do { \
sbuf_printf(sb, "\t%s: %03u\n", name, \
@@ -258,11 +277,8 @@ amdhwp_dump_sysctl_handler(SYSCTL_HANDLER_ARGS)
sbuf_putc(sb, '\n');
out:
- thread_lock(curthread);
- sched_unbind(curthread);
- thread_unlock(curthread);
-
- ret = sbuf_finish(sb);
+ if (ret == 0)
+ ret = sbuf_finish(sb);
if (ret == 0)
ret = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb));
sbuf_delete(sb);
@@ -270,44 +286,29 @@ out:
return (ret);
}
-static bool
-sysctl_epp_select_per_core(const device_t hwp_device, uint32_t val)
+static void
+sysctl_epp_select_per_core(device_t hwp_device, uint32_t val)
{
struct hwpstate_softc *sc;
- bool success = true;
- int ret, cpuid;
- cpuid = cpu_get_pcpu(hwp_device)->pc_cpuid;
- thread_lock(curthread);
- sched_bind(curthread, cpuid);
- thread_unlock(curthread);
sc = device_get_softc(hwp_device);
if (BITS_VALUE(AMD_CPPC_REQUEST_ENERGY_PERF_BITS, sc->req) == val)
- goto end;
+ return;
SET_BITS_VALUE(sc->req, AMD_CPPC_REQUEST_ENERGY_PERF_BITS, val);
- ret = wrmsr_safe(MSR_AMD_CPPC_REQUEST, sc->req);
- if (ret != 0) {
- success = false;
- device_printf(hwp_device, "Failed to set EPP to %u", val);
- goto end;
- }
-
-end:
- thread_lock(curthread);
- sched_unbind(curthread);
- thread_unlock(curthread);
-
- return (success);
+ x86_msr_op(MSR_AMD_CPPC_REQUEST,
+ MSR_OP_RENDEZVOUS_ONE | MSR_OP_WRITE |
+ MSR_OP_CPUID(cpu_get_pcpu(hwp_device)->pc_cpuid),
+ sc->req, NULL);
}
static int
sysctl_epp_select(SYSCTL_HANDLER_ARGS)
{
device_t dev, hwp_dev;
+ devclass_t dc;
struct hwpstate_softc *sc;
const uint32_t max_energy_perf =
BITS_VALUE(AMD_CPPC_REQUEST_ENERGY_PERF_BITS, (uint64_t)-1);
- devclass_t dc;
uint32_t val;
int ret = 0;
int cpu;
@@ -577,44 +578,45 @@ hwpstate_identify(driver_t *driver, device_t parent)
device_printf(parent, "hwpstate: add child failed\n");
}
-static int
-amd_set_autonomous_hwp(struct hwpstate_softc *sc)
+struct amd_set_autonomous_hwp_request {
+ device_t dev;
+ int res;
+};
+
+static void
+amd_set_autonomous_hwp_cb(void *args)
{
- struct pcpu *pc;
+ struct hwpstate_softc *sc;
+ struct amd_set_autonomous_hwp_request *req =
+ (struct amd_set_autonomous_hwp_request *)args;
device_t dev;
uint64_t caps;
int ret;
- dev = sc->dev;
- pc = cpu_get_pcpu(dev);
- if (pc == NULL)
- return (ENXIO);
-
- thread_lock(curthread);
- sched_bind(curthread, pc->pc_cpuid);
- thread_unlock(curthread);
-
+ dev = req->dev;
+ sc = device_get_softc(dev);
ret = wrmsr_safe(MSR_AMD_CPPC_ENABLE, 1);
if (ret != 0) {
device_printf(dev, "Failed to enable cppc for cpu%d (%d)\n",
- pc->pc_cpuid, ret);
- goto out;
+ curcpu, ret);
+ req->res = ret;
}
ret = rdmsr_safe(MSR_AMD_CPPC_REQUEST, &sc->req);
if (ret != 0) {
device_printf(dev,
- "Failed to read CPPC request MSR for cpu%d (%d)\n",
- pc->pc_cpuid, ret);
- goto out;
+ "Failed to read CPPC request MSR for cpu%d (%d)\n", curcpu,
+ ret);
+ req->res = ret;
}
ret = rdmsr_safe(MSR_AMD_CPPC_CAPS_1, &caps);
if (ret != 0) {
device_printf(dev,
"Failed to read HWP capabilities MSR for cpu%d (%d)\n",
- pc->pc_cpuid, ret);
- goto out;
+ curcpu, ret);
+ req->res = ret;
+ return;
}
/*
@@ -632,17 +634,27 @@ amd_set_autonomous_hwp(struct hwpstate_softc *sc)
ret = wrmsr_safe(MSR_AMD_CPPC_REQUEST, sc->req);
if (ret) {
- device_printf(dev,
- "Failed to setup autonomous HWP for cpu%d\n",
- pc->pc_cpuid);
- goto out;
+ device_printf(dev, "Failed to setup autonomous HWP for cpu%d\n",
+ curcpu);
+ req->res = ret;
+ return;
}
-out:
- thread_lock(curthread);
- sched_unbind(curthread);
- thread_unlock(curthread);
+ req->res = 0;
+}
- return (ret);
+static int
+amd_set_autonomous_hwp(struct hwpstate_softc *sc)
+{
+ struct amd_set_autonomous_hwp_request req;
+ device_t dev;
+
+ dev = sc->dev;
+ req.dev = dev;
+ smp_rendezvous_cpu(cpu_get_pcpu(dev)->pc_cpuid,
+ smp_no_rendezvous_barrier, amd_set_autonomous_hwp_cb,
+ smp_no_rendezvous_barrier, &req);
+
+ return (req.res);
}
static int