* [PATCH] turbostat: Running on virtual machine is not supported
@ 2017-07-25 12:55 Prarit Bhargava
2017-07-25 15:59 ` Henrique de Moraes Holschuh
0 siblings, 1 reply; 6+ messages in thread
From: Prarit Bhargava @ 2017-07-25 12:55 UTC (permalink / raw)
To: linux-kernel; +Cc: Prarit Bhargava, Len Brown, Len Brown
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.
A common way of determining if the system is a virtual machine is to
search /proc/cpuinfo flags entry for "hypervisor". turbostat must output
a proper error message when found.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Len Brown <lenb@kernel.org>
---
tools/power/x86/turbostat/turbostat.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 0dafba2c1e7d..ca1ea68bc4e8 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -5088,6 +5088,34 @@ void cmdline(int argc, char **argv)
}
}
+int has_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);
+
+ return !!hypervisor;
+}
+
int main(int argc, char **argv)
{
outf = stderr;
@@ -5097,6 +5125,12 @@ int main(int argc, char **argv)
if (!quiet)
print_version();
+ if (has_hypervisor()) {
+ fprintf(outf,
+ "turbostat is not supported on virtual machines.\n");
+ return -ENXIO;
+ }
+
probe_sysfs();
turbostat_init();
--
1.8.5.5
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] turbostat: Running on virtual machine is not supported
2017-07-25 12:55 [PATCH] turbostat: Running on virtual machine is not supported Prarit Bhargava
@ 2017-07-25 15:59 ` Henrique de Moraes Holschuh
2017-07-27 3:09 ` Len Brown
0 siblings, 1 reply; 6+ messages in thread
From: Henrique de Moraes Holschuh @ 2017-07-25 15:59 UTC (permalink / raw)
To: Prarit Bhargava; +Cc: linux-kernel, Len Brown, Len Brown
On Tue, 25 Jul 2017, Prarit Bhargava wrote:
> A common way of determining if the system is a virtual machine is to
> search /proc/cpuinfo flags entry for "hypervisor". turbostat must output
> a proper error message when found.
Maybe you could output that message only if it fails to both use
/dev/msr and perf *and* it is under a virtual machine? That would have
better forward compatibility, maybe someday /dev/msr or perf will work
inside a VM for what turbostat needs...
--
Henrique Holschuh
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] turbostat: Running on virtual machine is not supported
2017-07-25 15:59 ` Henrique de Moraes Holschuh
@ 2017-07-27 3:09 ` Len Brown
2017-07-27 11:44 ` Prarit Bhargava
2017-07-28 11:54 ` Prarit Bhargava
0 siblings, 2 replies; 6+ messages in thread
From: Len Brown @ 2017-07-27 3:09 UTC (permalink / raw)
To: Henrique de Moraes Holschuh
Cc: Prarit Bhargava, linux-kernel@vger.kernel.org, Len Brown
Henrique,
I like your suggestion, thanks!
BTW. let's discuss (and patch) turbostat on linux-pm, rather than on lkml.
thanks,
-Len
On Tue, Jul 25, 2017 at 11:59 AM, Henrique de Moraes Holschuh
<hmh@hmh.eng.br> wrote:
> On Tue, 25 Jul 2017, Prarit Bhargava wrote:
>> A common way of determining if the system is a virtual machine is to
>> search /proc/cpuinfo flags entry for "hypervisor". turbostat must output
>> a proper error message when found.
>
> Maybe you could output that message only if it fails to both use
> /dev/msr and perf *and* it is under a virtual machine? That would have
> better forward compatibility, maybe someday /dev/msr or perf will work
> inside a VM for what turbostat needs...
>
> --
> Henrique Holschuh
--
Len Brown, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] turbostat: Running on virtual machine is not supported
2017-07-27 3:09 ` Len Brown
@ 2017-07-27 11:44 ` Prarit Bhargava
2017-08-05 6:39 ` Len Brown
2017-07-28 11:54 ` Prarit Bhargava
1 sibling, 1 reply; 6+ messages in thread
From: Prarit Bhargava @ 2017-07-27 11:44 UTC (permalink / raw)
To: Len Brown, Henrique de Moraes Holschuh
Cc: linux-kernel@vger.kernel.org, Len Brown
On 07/26/2017 11:09 PM, Len Brown wrote:
> Henrique,
>
> I like your suggestion, thanks!
>
> BTW. let's discuss (and patch) turbostat on linux-pm, rather than on lkml.
Sure -- Len, can you add an entry to RHMAINTAINERS for that? I use the
get_maintainer.pl script to apply all cc's.
P.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] turbostat: Running on virtual machine is not supported
2017-07-27 11:44 ` Prarit Bhargava
@ 2017-08-05 6:39 ` Len Brown
0 siblings, 0 replies; 6+ messages in thread
From: Len Brown @ 2017-08-05 6:39 UTC (permalink / raw)
To: Prarit Bhargava
Cc: Henrique de Moraes Holschuh, linux-kernel@vger.kernel.org,
Len Brown
[-- Attachment #1: Type: text/plain, Size: 72 bytes --]
> Len, can you add an entry to RHMAINTAINERS for that?
done.
thx.
Len
[-- Attachment #2: 0001-MAINTAINERS-add-turbostat-utility.patch --]
[-- Type: application/octet-stream, Size: 1110 bytes --]
From a71ec6b6c6ce93fa07f2c6df1dfa69871f08cb5b Mon Sep 17 00:00:00 2001
Message-Id: <a71ec6b6c6ce93fa07f2c6df1dfa69871f08cb5b.1501915126.git.len.brown@intel.com>
From: Len Brown <len.brown@intel.com>
Date: Sat, 5 Aug 2017 02:36:50 -0400
Subject: [PATCH 01/14] MAINTAINERS: add turbostat utility
Reply-To: Len Brown <lenb@kernel.org>
Organization: Intel Open Source Technology Center
Signed-off-by: Len Brown <len.brown@intel.com>
---
MAINTAINERS | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index 7a28acd7f525..cb94ef6412b1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13033,6 +13033,15 @@ S: Maintained
F: drivers/tc/
F: include/linux/tc.h
+TURBOSTAT UTILITY
+M: "Len Brown" <lenb@kernel.org>
+L: linux-pm@vger.kernel.org
+B: https://bugzilla.kernel.org
+Q: https://patchwork.kernel.org/project/linux-pm/list/
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux.git turbostat
+S: Supported
+F: tools/power/x86/turbostat/
+
UBI FILE SYSTEM (UBIFS)
M: Richard Weinberger <richard@nod.at>
M: Artem Bityutskiy <dedekind1@gmail.com>
--
2.14.0-rc0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] turbostat: Running on virtual machine is not supported
2017-07-27 3:09 ` Len Brown
2017-07-27 11:44 ` Prarit Bhargava
@ 2017-07-28 11:54 ` Prarit Bhargava
1 sibling, 0 replies; 6+ messages in thread
From: Prarit Bhargava @ 2017-07-28 11:54 UTC (permalink / raw)
To: Len Brown, Henrique de Moraes Holschuh
Cc: linux-kernel@vger.kernel.org, Len Brown, linux-pm@vger.kernel.org
On 07/26/2017 11:09 PM, Len Brown wrote:
> Henrique,
>
> I like your suggestion, thanks!
>
> BTW. let's discuss (and patch) turbostat on linux-pm, rather than on lkml.
>
> thanks,
> -Len
>
>
> On Tue, Jul 25, 2017 at 11:59 AM, Henrique de Moraes Holschuh
> <hmh@hmh.eng.br> wrote:
>> On Tue, 25 Jul 2017, Prarit Bhargava wrote:
>>> A common way of determining if the system is a virtual machine is to
>>> search /proc/cpuinfo flags entry for "hypervisor". turbostat must output
>>> a proper error message when found.
>>
>> Maybe you could output that message only if it fails to both use
>> /dev/msr and perf *and* it is under a virtual machine? That would have
>> better forward compatibility, maybe someday /dev/msr or perf will work
>> inside a VM for what turbostat needs...
To answer Len's previous question: I was wrong in my description. perf does
work (mostly) under virt. So this would only be for the msr code. I'll post a
v2 to linux-pm, and take Henrique's suggestion to only trigger on an msr read
failure.
P.
>>
>> --
>> Henrique Holschuh
>
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-08-05 6:39 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2017-07-25 12:55 [PATCH] turbostat: Running on virtual machine is not supported Prarit Bhargava
2017-07-25 15:59 ` Henrique de Moraes Holschuh
2017-07-27 3:09 ` Len Brown
2017-07-27 11:44 ` Prarit Bhargava
2017-08-05 6:39 ` Len Brown
2017-07-28 11:54 ` Prarit Bhargava
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