From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
To: Nathan Lynch <nathanl@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
Tyrel Datwyler <tyreld@linux.ibm.com>
Cc: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 3/5] powerpc/pseries: Account for SPURR ticks on idle CPUs
Date: Fri, 21 Feb 2020 10:48:32 +0530 [thread overview]
Message-ID: <1582262314-8319-4-git-send-email-ego@linux.vnet.ibm.com> (raw)
In-Reply-To: <1582262314-8319-1-git-send-email-ego@linux.vnet.ibm.com>
From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
On Pseries LPARs, to calculate utilization, we need to know the
[S]PURR ticks when the CPUs were busy or idle.
Via idle_loop_prolog(), idle_loop_epilog(), we track the idle PURR
ticks in the VPA variable "wait_state_cycles". This patch extends the
support to account for the idle SPURR ticks. It also provides an
accessor function to accurately reads idle SPURR ticks.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/idle.h | 33 +++++++++++++++++++++++++++++++++
arch/powerpc/platforms/pseries/setup.c | 2 ++
2 files changed, 35 insertions(+)
diff --git a/arch/powerpc/include/asm/idle.h b/arch/powerpc/include/asm/idle.h
index 126a217..db82fc1 100644
--- a/arch/powerpc/include/asm/idle.h
+++ b/arch/powerpc/include/asm/idle.h
@@ -2,13 +2,20 @@
#define _ASM_POWERPC_IDLE_H
#include <asm/runlatch.h>
+DECLARE_PER_CPU(u64, idle_spurr_cycles);
DECLARE_PER_CPU(u64, idle_entry_purr_snap);
+DECLARE_PER_CPU(u64, idle_entry_spurr_snap);
static inline void snapshot_purr_idle_entry(void)
{
*this_cpu_ptr(&idle_entry_purr_snap) = mfspr(SPRN_PURR);
}
+static inline void snapshot_spurr_idle_entry(void)
+{
+ *this_cpu_ptr(&idle_entry_spurr_snap) = mfspr(SPRN_SPURR);
+}
+
static inline void update_idle_purr_accounting(void)
{
u64 wait_cycles;
@@ -19,10 +26,19 @@ static inline void update_idle_purr_accounting(void)
get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles);
}
+static inline void update_idle_spurr_accounting(void)
+{
+ u64 *idle_spurr_cycles_ptr = this_cpu_ptr(&idle_spurr_cycles);
+ u64 in_spurr = *this_cpu_ptr(&idle_entry_spurr_snap);
+
+ *idle_spurr_cycles_ptr += mfspr(SPRN_SPURR) - in_spurr;
+}
+
static inline void idle_loop_prolog(void)
{
ppc64_runlatch_off();
snapshot_purr_idle_entry();
+ snapshot_spurr_idle_entry();
/*
* Indicate to the HV that we are idle. Now would be
* a good time to find other work to dispatch.
@@ -33,6 +49,7 @@ static inline void idle_loop_prolog(void)
static inline void idle_loop_epilog(void)
{
update_idle_purr_accounting();
+ update_idle_spurr_accounting();
get_lppaca()->idle = 0;
ppc64_runlatch_on();
}
@@ -52,4 +69,20 @@ static inline u64 read_this_idle_purr(void)
return be64_to_cpu(get_lppaca()->wait_state_cycles);
}
+
+static inline u64 read_this_idle_spurr(void)
+{
+ /*
+ * If we are reading from an idle context, update the
+ * idle-spurr cycles corresponding to the last idle period.
+ * Since the idle context is not yet over, take a fresh
+ * snapshot of the idle-spurr.
+ */
+ if (get_lppaca()->idle == 1) {
+ update_idle_spurr_accounting();
+ snapshot_spurr_idle_entry();
+ }
+
+ return *this_cpu_ptr(&idle_spurr_cycles);
+}
#endif
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index e9f2cefa..5ef5c82 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -318,7 +318,9 @@ static int alloc_dispatch_log_kmem_cache(void)
}
machine_early_initcall(pseries, alloc_dispatch_log_kmem_cache);
+DEFINE_PER_CPU(u64, idle_spurr_cycles);
DEFINE_PER_CPU(u64, idle_entry_purr_snap);
+DEFINE_PER_CPU(u64, idle_entry_spurr_snap);
static void pseries_lpar_idle(void)
{
/*
--
1.9.4
next prev parent reply other threads:[~2020-02-21 5:26 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 5:18 [PATCH v2 0/5] Track and expose idle PURR and SPURR ticks Gautham R. Shenoy
2020-02-21 5:18 ` [PATCH v2 1/5] powerpc: Move idle_loop_prolog()/epilog() functions to header file Gautham R. Shenoy
2020-02-21 15:03 ` Nathan Lynch
2020-02-24 4:55 ` Gautham R Shenoy
2020-03-06 17:06 ` Nathan Lynch
2020-02-21 5:18 ` [PATCH v2 2/5] powerpc/idle: Add accessor function to always read latest idle PURR Gautham R. Shenoy
2020-02-21 5:18 ` Gautham R. Shenoy [this message]
2020-02-21 16:47 ` [PATCH v2 3/5] powerpc/pseries: Account for SPURR ticks on idle CPUs Nathan Lynch
2020-02-24 5:05 ` Gautham R Shenoy
2020-02-21 5:18 ` [PATCH v2 4/5] powerpc/sysfs: Show idle_purr and idle_spurr for every CPU Gautham R. Shenoy
2020-02-21 16:50 ` Nathan Lynch
2020-02-24 5:14 ` Gautham R Shenoy
2020-02-25 10:20 ` Naveen N. Rao
2020-03-06 17:03 ` Nathan Lynch
2020-03-06 17:35 ` Naveen N. Rao
2020-02-21 5:18 ` [PATCH v2 5/5] Documentation: Document sysfs interfaces purr, spurr, idle_purr, idle_spurr Gautham R. Shenoy
2020-02-21 16:55 ` Nathan Lynch
2020-02-24 5:15 ` Gautham R Shenoy
2020-02-24 4:17 ` [PATCH v2 0/5] Track and expose idle PURR and SPURR ticks Kamalesh Babulal
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