[PATCH v10 1/3] /proc/pid/status: Add support for architecture specific output

[PATCH v10 1/3] /proc/pid/status: Add support for architecture specific output

[Aubrey Li]

The architecture specific information of the running processes could
be useful to the userland. Add support to examine process architecture
specific information externally.

Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
---
 fs/proc/array.c         | 5 +++++
 include/linux/proc_fs.h | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 9d428d5a0ac8..ea7a981f289c 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -401,6 +401,10 @@ static inline void task_thp_status(struct seq_file *m, struct mm_struct *mm)
 	seq_printf(m, "THP_enabled:\t%d\n", thp_enabled);
 }
 
+void __weak arch_proc_pid_status(struct seq_file *m, struct task_struct *task)
+{
+}
+
 int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
 			struct pid *pid, struct task_struct *task)
 {
@@ -424,6 +428,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
 	task_cpus_allowed(m, task);
 	cpuset_task_status_allowed(m, task);
 	task_context_switch_counts(m, task);
+	arch_proc_pid_status(m, task);
 	return 0;
 }
 
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index d0e1f1522a78..1de9ba1b064f 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -73,6 +73,8 @@ struct proc_dir_entry *proc_create_net_single_write(const char *name, umode_t mo
 						    int (*show)(struct seq_file *, void *),
 						    proc_write_t write,
 						    void *data);
+/* Add support for architecture specific output in /proc/pid/status */
+extern void arch_proc_pid_status(struct seq_file *m, struct task_struct *task);
 
 #else /* CONFIG_PROC_FS */
 
-- 
2.17.1

[PATCH v10 2/3] x86,/proc/pid/status: Add AVX-512 usage elapsed time

[Aubrey Li]

AVX-512 components use could cause core turbo frequency drop. So
it's useful to expose AVX-512 usage elapsed time as a heuristic hint
for the user space job scheduler to cluster the AVX-512 using tasks
together.

Example:
$ cat /proc/pid/status | grep AVX512_elapsed_ms
AVX512_elapsed_ms:      1020

The number '1020' denotes 1020 millisecond elapsed since last time
context switch the off-CPU task using AVX-512 components, thus the
task could cause core frequency drop.

Or:
$ cat /proc/pid/status | grep AVX512_elapsed_ms
AVX512_elapsed_ms:      -1

The number '-1' indicates the task didn't use AVX-512 components
before thus unlikely has frequency drop issue.

User space tools may want to further check by:

$ perf stat --pid <pid> -e core_power.lvl2_turbo_license -- sleep 1

 Performance counter stats for process id '3558':

     3,251,565,961      core_power.lvl2_turbo_license

       1.004031387 seconds time elapsed

Non-zero counter value confirms that the task causes frequency drop.

Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
---
 arch/x86/kernel/fpu/xstate.c | 41 ++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 9cc108456d0b..c42a233f26f1 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -7,6 +7,7 @@
 #include <linux/cpu.h>
 #include <linux/mman.h>
 #include <linux/pkeys.h>
+#include <linux/seq_file.h>
 
 #include <asm/fpu/api.h>
 #include <asm/fpu/internal.h>
@@ -1243,3 +1244,43 @@ int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf)
 
 	return 0;
 }
+
+/*
+ * Report the amount of time elapsed in millisecond since last AVX512
+ * use in the task.
+ */
+void avx512_status(struct seq_file *m, struct task_struct *task)
+{
+	unsigned long timestamp = task->thread.fpu.avx512_timestamp;
+	long delta;
+
+	if (!timestamp) {
+		/*
+		 * Report -1 if no AVX512 usage
+		 */
+		delta = -1;
+	} else {
+		delta = (long)(jiffies - timestamp);
+		/*
+		 * Cap to LONG_MAX if time difference > LONG_MAX
+		 */
+		if (delta < 0)
+			delta = LONG_MAX;
+		delta = jiffies_to_msecs(delta);
+	}
+
+	seq_put_decimal_ll(m, "AVX512_elapsed_ms:\t", delta);
+	seq_putc(m, '\n');
+}
+
+/*
+ * Report architecture specific information
+ */
+void arch_proc_pid_status(struct seq_file *m, struct task_struct *task)
+{
+	/*
+	 * Report AVX512 state if the processor and build option supported.
+	 */
+	if (cpu_feature_enabled(X86_FEATURE_AVX512F))
+		avx512_status(m, task);
+}
-- 
2.17.1

[PATCH v10 3/3] Documentation/filesystems/proc.txt: add AVX512_elapsed_ms

[Aubrey Li]

Added AVX512_elapsed_ms in /proc/<pid>/status. Report it
in Documentation/filesystems/proc.txt

Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
---
 Documentation/filesystems/proc.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 66cad5c86171..8da60ddcda7f 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -207,6 +207,7 @@ read the file /proc/PID/status:
   Speculation_Store_Bypass:       thread vulnerable
   voluntary_ctxt_switches:        0
   nonvoluntary_ctxt_switches:     1
+  AVX512_elapsed_ms:	1020
 
 This shows you nearly the same information you would get if you viewed it with
 the ps  command.  In  fact,  ps  uses  the  proc  file  system  to  obtain its
@@ -224,7 +225,7 @@ asynchronous manner and the value may not be very precise. To see a precise
 snapshot of a moment, you can see /proc/<pid>/smaps file and scan page table.
 It's slow but very precise.
 
-Table 1-2: Contents of the status files (as of 4.19)
+Table 1-2: Contents of the status files (as of 5.1)
 ..............................................................................
  Field                       Content
  Name                        filename of the executable
@@ -289,6 +290,7 @@ Table 1-2: Contents of the status files (as of 4.19)
  Mems_allowed_list           Same as previous, but in "list format"
  voluntary_ctxt_switches     number of voluntary context switches
  nonvoluntary_ctxt_switches  number of non voluntary context switches
+ AVX512_elapsed_ms           time elapsed since last AVX512 use in millisecond
 ..............................................................................
 
 Table 1-3: Contents of the statm files (as of 2.6.8-rc3)
-- 
2.17.1

Re: [PATCH v10 2/3] x86,/proc/pid/status: Add AVX-512 usage elapsed time

[Thomas Gleixner]

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On Tue, 12 Feb 2019, Aubrey Li wrote:

arch/x86/kernel/fpu/xstate.c:1252:6: warning: no previous prototype for ‘avx512_status’ [-Wmissing-prototypes]
 void avx512_status(struct seq_file *m, struct task_struct *task)
      ^~~~~~~~~~~~~
arch/x86/kernel/fpu/xstate.c: In function ‘avx512_status’:
arch/x86/kernel/fpu/xstate.c:1254:44: error: ‘struct fpu’ has no member named ‘avx512_timestamp’
  unsigned long timestamp = task->thread.fpu.avx512_timestamp;
                                            ^
arch/x86/kernel/fpu/xstate.c: At top level:
arch/x86/kernel/fpu/xstate.c:1279:6: warning: no previous prototype for ‘arch_proc_pid_status’ [-Wmissing-prototypes]
 void arch_proc_pid_status(struct seq_file *m, struct task_struct *task)
      ^~~~~~~~~~~~~~~~~~~~

I'm tired of this. 

Thanks,

	tglx

Re: [PATCH v10 2/3] x86,/proc/pid/status: Add AVX-512 usage elapsed time

[Li, Aubrey]

On 2019/2/12 21:03, Thomas Gleixner wrote:
> On Tue, 12 Feb 2019, Aubrey Li wrote:
> 
> arch/x86/kernel/fpu/xstate.c:1252:6: warning: no previous prototype for ‘avx512_status’ [-Wmissing-prototypes]
>  void avx512_status(struct seq_file *m, struct task_struct *task)
>       ^~~~~~~~~~~~~
Sorry for this warning, I didn't see it on my side. May I know how to open this knob?

> arch/x86/kernel/fpu/xstate.c: In function ‘avx512_status’:
> arch/x86/kernel/fpu/xstate.c:1254:44: error: ‘struct fpu’ has no member named ‘avx512_timestamp’
>   unsigned long timestamp = task->thread.fpu.avx512_timestamp;

I didn't include the first patch, because I saw it's already in tip tree. Did you use tip tree?

>                                             ^
> arch/x86/kernel/fpu/xstate.c: At top level:
> arch/x86/kernel/fpu/xstate.c:1279:6: warning: no previous prototype for ‘arch_proc_pid_status’ [-Wmissing-prototypes]
>  void arch_proc_pid_status(struct seq_file *m, struct task_struct *task)
>       ^~~~~~~~~~~~~~~~~~~~
Sorry for this, May I know how to replicate it on my side?

Thanks,
-Aubrey

Re: [PATCH v10 2/3] x86,/proc/pid/status: Add AVX-512 usage elapsed time

[Thomas Gleixner]

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On Tue, 12 Feb 2019, Li, Aubrey wrote:

> On 2019/2/12 21:03, Thomas Gleixner wrote:
> I didn't include the first patch, because I saw it's already in tip
> tree. Did you use tip tree?

Yes, that's my bad, forgot to switch branches. That still does not solve:

> > arch/x86/kernel/fpu/xstate.c: At top level:
> > arch/x86/kernel/fpu/xstate.c:1279:6: warning: no previous prototype for ‘arch_proc_pid_status’ [-Wmissing-prototypes]
> >  void arch_proc_pid_status(struct seq_file *m, struct task_struct *task)
> >       ^~~~~~~~~~~~~~~~~~~~
> Sorry for this, May I know how to replicate it on my side?

make W=1 ....

And please take your time and do not shoot out half baken patch series
every 5 minutes.

Thanks,

	tglx

Re: [PATCH v10 2/3] x86,/proc/pid/status: Add AVX-512 usage elapsed time

[Thomas Gleixner]

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On Tue, 12 Feb 2019, Thomas Gleixner wrote:

> On Tue, 12 Feb 2019, Li, Aubrey wrote:
> 
> > On 2019/2/12 21:03, Thomas Gleixner wrote:
> > I didn't include the first patch, because I saw it's already in tip
> > tree. Did you use tip tree?
> 
> Yes, that's my bad, forgot to switch branches. That still does not solve:
> 
> > > arch/x86/kernel/fpu/xstate.c: At top level:
> > > arch/x86/kernel/fpu/xstate.c:1279:6: warning: no previous prototype for ‘arch_proc_pid_status’ [-Wmissing-prototypes]
> > >  void arch_proc_pid_status(struct seq_file *m, struct task_struct *task)
> > >       ^~~~~~~~~~~~~~~~~~~~
> > Sorry for this, May I know how to replicate it on my side?
> 
> make W=1 ....

Aside of that I didn't have to compile that simply because it was obvious
that nothing includes procfs.h in that file ...

Thanks,

	tglx

Re: [PATCH v10 2/3] x86,/proc/pid/status: Add AVX-512 usage elapsed time

[Li, Aubrey]

On 2019/2/12 21:24, Thomas Gleixner wrote:
> On Tue, 12 Feb 2019, Li, Aubrey wrote:
> 
>> On 2019/2/12 21:03, Thomas Gleixner wrote:
>> I didn't include the first patch, because I saw it's already in tip
>> tree. Did you use tip tree?
> 
> Yes, that's my bad, forgot to switch branches. That still does not solve:
> 
>>> arch/x86/kernel/fpu/xstate.c: At top level:
>>> arch/x86/kernel/fpu/xstate.c:1279:6: warning: no previous prototype for ‘arch_proc_pid_status’ [-Wmissing-prototypes]
>>>  void arch_proc_pid_status(struct seq_file *m, struct task_struct *task)
>>>       ^~~~~~~~~~~~~~~~~~~~
>> Sorry for this, May I know how to replicate it on my side?
> 
> make W=1 ....

This works, thanks!

> 
> And please take your time and do not shoot out half baken patch series
> every 5 minutes.
> 
Sorry for the trouble, just want to solve the problem before your eyes move
away from this thread.

Thanks,
-Aubrey

Re: [PATCH v10 2/3] x86,/proc/pid/status: Add AVX-512 usage elapsed time

[Thomas Gleixner]

On Tue, 12 Feb 2019, Li, Aubrey wrote:
> On 2019/2/12 21:24, Thomas Gleixner wrote:
> > And please take your time and do not shoot out half baken patch series
> > every 5 minutes.
> > 
> Sorry for the trouble, just want to solve the problem before your eyes move
> away from this thread.

You achieve exactly the opposite of what you are trying to do. If I get
repeated half baken crap, that surely does not foster my interest.

Thanks,

	tglx