linux-pm.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v2] turbostat: Running on virtual machine is not supported
@ 2017-07-28 11:58 Prarit Bhargava
  0 siblings, 0 replies; 2+ messages in thread
From: Prarit Bhargava @ 2017-07-28 11:58 UTC (permalink / raw)
  To: linux-pm; +Cc: Prarit Bhargava, Len Brown, Len Brown,
	Henrique de Moraes Holschuh

When running turbostat on a virtual machine the error

turbostat: msr 0 offset 0xe2 read failed: Input/output error

is output to the user.

/dev/msr and perf do not work on a virtual machine.  turbostat is
dependent on that support so turbostat does not work either.

When an error is returned from an msr read, turbostat must check to see if
the system is a virtual machine and return an error to the user.

[v2]: Only check for VM if msr read fails

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
---
 tools/power/x86/turbostat/turbostat.c | 57 +++++++++++++++++++++++++++--------
 1 file changed, 45 insertions(+), 12 deletions(-)

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 0dafba2c1e7d..97c51bdce2ef 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -333,14 +333,58 @@ int get_msr_fd(int cpu)
 	return fd;
 }
 
+/*
+ * Open a file, and exit on failure
+ */
+FILE *fopen_or_die(const char *path, const char *mode)
+{
+	FILE *filep = fopen(path, mode);
+
+	if (!filep)
+		err(1, "%s: open failed", path);
+	return filep;
+}
+
+void err_on_hypervisor(void)
+{
+	FILE *cpuinfo;
+	char *flags, *hypervisor;
+	char *buffer;
+
+	/* On VMs /proc/cpuinfo contains a "flags" entry for hypervisor */
+	cpuinfo = fopen_or_die("/proc/cpuinfo", "ro");
+
+	buffer = malloc(4096);
+	if (!buffer)
+		err(-ENOMEM, "buffer malloc fail");
+
+	fread(buffer, 1024, 1, cpuinfo);
+
+	flags = strstr(buffer, "flags");
+	rewind(cpuinfo);
+	fseek(cpuinfo, flags - buffer, SEEK_SET);
+	fgets(buffer, 4096, cpuinfo);
+	fclose(cpuinfo);
+
+	hypervisor = strstr(buffer, "hypervisor");
+
+	free(buffer);
+
+	if (hypervisor)
+		err(-1,
+		    "turbostat is not supported on this virtual machine.");
+}
+
 int get_msr(int cpu, off_t offset, unsigned long long *msr)
 {
 	ssize_t retval;
 
 	retval = pread(get_msr_fd(cpu), msr, sizeof(*msr), offset);
 
-	if (retval != sizeof *msr)
+	if (retval != sizeof *msr) {
+		err_on_hypervisor();
 		err(-1, "cpu%d: msr offset 0x%llx read failed", cpu, (unsigned long long)offset);
+	}
 
 	return 0;
 }
@@ -1453,17 +1497,6 @@ static unsigned long long rdtsc(void)
 }
 
 /*
- * Open a file, and exit on failure
- */
-FILE *fopen_or_die(const char *path, const char *mode)
-{
-	FILE *filep = fopen(path, mode);
-
-	if (!filep)
-		err(1, "%s: open failed", path);
-	return filep;
-}
-/*
  * snapshot_sysfs_counter()
  *
  * return snapshot of given counter
-- 
1.8.5.5

^ permalink raw reply related	[flat|nested] 2+ messages in thread
* [PATCH 0/7 RESEND] turbostat: Fix AMD output by making turbostat aware of nodes
@ 2017-07-28 12:06 Prarit Bhargava
  2017-07-28 12:06 ` [PATCH v2] turbostat: Running on virtual machine is not supported Prarit Bhargava
  0 siblings, 1 reply; 2+ messages in thread
From: Prarit Bhargava @ 2017-07-28 12:06 UTC (permalink / raw)
  To: linux-pm; +Cc: lenb, Prarit Bhargava, Len Brown

[Sending to linux-pm instead of linux-kernel ...]

AMD family processors do not show all cores in the output of turbostat.  This
occurs because AMD has multiple nodes per socket and enumerates cores
within each node from 0.  For example, socket 0 may have two nodes (0 and 1)
and those nodes both have cores enumerated from 0 through 7.  turbostat cannot
handle this configuration, and as a result only shows 1/2 the cores in its
output.

This patchset makes turbostate aware of nodes.  It has been tested on
various AMD and Intel systems and no issues have been found.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Len Brown <len.brown@intel.com>

Prarit Bhargava (7):
  turbostat: set max_num_cpus equal to the cpumask length
  turbostat: Fix node and siblings lookup data
  turbostat: Calculate additional node information for a package
  turbostat: track thread ID in cpu_topology
  turbostat: rename num_cores_per_pkg to num_cores_per_node
  turbostat: remove num_ from cpu_topology struct
  turbostat: add node information into turbostat calculations

 tools/power/x86/turbostat/turbostat.c | 419 +++++++++++++++++++++-------------
 1 file changed, 259 insertions(+), 160 deletions(-)

-- 
1.8.5.5

^ permalink raw reply	[flat|nested] 2+ messages in thread
end of thread, other threads:[~2017-07-28 12:06 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-07-28 11:58 [PATCH v2] turbostat: Running on virtual machine is not supported Prarit Bhargava
  -- strict thread matches above, loose matches on Subject: below --
2017-07-28 12:06 [PATCH 0/7 RESEND] turbostat: Fix AMD output by making turbostat aware of nodes Prarit Bhargava
2017-07-28 12:06 ` [PATCH v2] turbostat: Running on virtual machine is not supported Prarit Bhargava

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).