Re: [PATCH v4 1/2] drivers: hv: vmbus: Introduce latency testing

2019-09-05 Thread Branden Bonaby 
On Mon, Sep 02, 2019 at 06:31:04PM +, Michael Kelley wrote:
> From: Branden Bonaby  Sent: Wednesday, August 28, 
> 2019 9:24 PM
> > 
> > Introduce user specified latency in the packet reception path
> > By exposing the test parameters as part of the debugfs channel
> > attributes. We will control the testing state via these attributes.
> > 
> > Signed-off-by: Branden Bonaby 
> > ---
> > diff --git a/Documentation/ABI/testing/debugfs-hyperv
> > b/Documentation/ABI/testing/debugfs-hyperv
> > new file mode 100644
> > index ..0903e6427a2d
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/debugfs-hyperv
> > @@ -0,0 +1,23 @@
> > +What:   /sys/kernel/debug/hyperv//fuzz_test_state
> > +Date:   August 2019
> > +KernelVersion:  5.3
> 
> Given the way the timing works for adding code to the Linux kernel,
> the earliest your new code will be included is 5.4.  The merge window
> for 5.4 will open in two weeks, so your code would need to be accepted
> by then to be included in 5.4.  Otherwise, it won't make it until the next
> merge window, which would be for 5.5.  I would suggest changing this
> (and the others below) to 5.4 for now, but you might have to change to
> 5.5 if additional revisions are needed.
> 

I see, I'll keep this in mind when submitting the further revisions
thanks

> > diff --git a/drivers/hv/Makefile b/drivers/hv/Makefile
> > index a1eec7177c2d..d754bd86ca47 100644
> > --- a/drivers/hv/Makefile
> > +++ b/drivers/hv/Makefile
> > @@ -2,6 +2,7 @@
> >  obj-$(CONFIG_HYPERV)   += hv_vmbus.o
> >  obj-$(CONFIG_HYPERV_UTILS) += hv_utils.o
> >  obj-$(CONFIG_HYPERV_BALLOON)   += hv_balloon.o
> > +obj-$(CONFIG_HYPERV_TESTING)   += hv_debugfs.o
> 
> There's an additional complexity here that I failed to describe to
> you in my previous comments.  :-(The above line makes the
> hv_debugfs code part of the main Linux OS image -- i.e., the
> vmlinuz file that gets installed into /boot, such that if hv_debugfs
> is built, it is always loaded into the memory of the running system.
> That's OK, but we should consider the alternative, which is to
> make the hv_debugfs code part of the hv_vmbus module that
> is specified a bit further down in the same Makefile.   A module
> is installed into /lib/modules//kernel, and
> is only loaded into memory on the running system if something
> actually references code in the module.  This approach helps avoid
> loading code into memory that isn't actually used.
> 
> Whether code is built as a separate module or is just built into
> the main vmlinuz file is also controlled by the .config file setting.
> For example, CONFIG_HYPERV=m says to treat hv_vmbus as a
> separate module, while CONFIG_HYPERV=y says to build the
> hv_vmbus module directly into the vmlinuz file even though the
> Makefile constructs it as a module.
> 
> Making hv_debugfs part of the hv_vmbus module is generally better
> than just building it into the main vmlinuz because it's best to include
> only things that must always be present in the main vmlinuz file.
> hv_debugfs doesn't have any reason it needs to always be present.
> By comparison, hv_balloon is included in the main vmlinuz, which
> might be due to it dealing with memory mgmt and needing to be
> in the vmlinuz image, but I'm not sure.
> 
> You can make hv_debugfs part of the hv_vmbus module with this line
> placed after the line specifying hv_vmbus_y, instead of the line you
> currently have:
> 
> hv_vmbus-$(CONFIG_HYPERV_TESTING)   += hv_debugfs.o
> 

Ah, I see now. That makes sense I'll go ahead and make the adjustments

thanks

> > +
> > +static int hv_debugfs_delay_set(void *data, u64 val)
> > +{
> > +   int ret = 0;
> > +
> > +   if (val >= 1 && val <= 1000)
> > +   *(u32 *)data = val;
> > +   else if (val == 0)
> > +   *(u32 *)data = 0;
> 
> I think this "else if" clause can be folded into the first
> "if" statement by just checking "val >= 0".
> 

good call, I'll fold it into one statement 

> 
> > +/* Remove dentry associated with released hv device */
> > +void hv_debug_rm_dev_dir(struct hv_device *dev)
> > +{
> > +   if (!IS_ERR(hv_debug_root))
> > +   debugfs_remove_recursive(dev->debug_dir);
> > +}
> 
> This function is the first of five functions that are called by
> code outside of hv_debugfs.c.   You probably saw the separate
> email from the kbuild test robot showing a build error on each
> of these five functions.  Here's why.
> 
> When CONFIG_HYPERV=m is set, and hv_vmbus is built as a
> module, there are references to the five functions from the
> module to your hv_debugfs that is built as core code in
> vmlinuz.  By default, Linux does not allow such core code to
> be called by modules.   Core code must add a statement like:
> 
> EXPORT_SYMBOL_GPL(hv_debug_rm_dev_dir);
> 
> to allow the module to call it.   This gives the code writer
> a very minimal amount of scope control.  However, if you build 
> hv_debugfs as part of the module hv_vmbus, and

RE: [PATCH v4 1/2] drivers: hv: vmbus: Introduce latency testing

2019-09-02 Thread Michael Kelley 
From: Branden Bonaby  Sent: Wednesday, August 28, 
2019 9:24 PM
> 
> Introduce user specified latency in the packet reception path
> By exposing the test parameters as part of the debugfs channel
> attributes. We will control the testing state via these attributes.
> 
> Signed-off-by: Branden Bonaby 
> ---
> diff --git a/Documentation/ABI/testing/debugfs-hyperv
> b/Documentation/ABI/testing/debugfs-hyperv
> new file mode 100644
> index ..0903e6427a2d
> --- /dev/null
> +++ b/Documentation/ABI/testing/debugfs-hyperv
> @@ -0,0 +1,23 @@
> +What:   /sys/kernel/debug/hyperv//fuzz_test_state
> +Date:   August 2019
> +KernelVersion:  5.3

Given the way the timing works for adding code to the Linux kernel,
the earliest your new code will be included is 5.4.  The merge window
for 5.4 will open in two weeks, so your code would need to be accepted
by then to be included in 5.4.  Otherwise, it won't make it until the next
merge window, which would be for 5.5.  I would suggest changing this
(and the others below) to 5.4 for now, but you might have to change to
5.5 if additional revisions are needed.

> +Contact:Branden Bonaby 
> +Description:Fuzz testing status of a vmbus device, whether its in an ON
> +state or a OFF state
> +Users:  Debugging tools
> +
> +What:   
> /sys/kernel/debug/hyperv//delay/fuzz_test_buffer_interrupt_delay
> +Date:   August 2019
> +KernelVersion:  5.3
> +Contact:Branden Bonaby 
> +Description:Fuzz testing buffer interrupt delay value between 0 - 1000
> +  microseconds (inclusive).
> +Users:  Debugging tools
> +
> +What:   /sys/kernel/debug/hyperv//delay/fuzz_test_message_delay
> +Date:   August 2019
> +KernelVersion:  5.3
> +Contact:Branden Bonaby 
> +Description:Fuzz testing message delay value between 0 - 1000 
> microseconds
> +  (inclusive).
> +Users:  Debugging tools
> diff --git a/MAINTAINERS b/MAINTAINERS
> index b1bc9c87838b..6931a4eeaac0 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7460,6 +7460,7 @@ F:  include/uapi/linux/hyperv.h
>  F:   include/asm-generic/mshyperv.h
>  F:   tools/hv/
>  F:   Documentation/ABI/stable/sysfs-bus-vmbus
> +F:   Documentation/ABI/testing/debugfs-hyperv
> 
>  HYPERBUS SUPPORT
>  M:   Vignesh Raghavendra 
> diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
> index 9a59957922d4..d97437ba0626 100644
> --- a/drivers/hv/Kconfig
> +++ b/drivers/hv/Kconfig
> @@ -29,4 +29,11 @@ config HYPERV_BALLOON
>   help
> Select this option to enable Hyper-V Balloon driver.
> 
> +config HYPERV_TESTING
> +bool "Hyper-V testing"
> +default n
> +depends on HYPERV && DEBUG_FS
> +help
> +  Select this option to enable Hyper-V vmbus testing.
> +
>  endmenu
> diff --git a/drivers/hv/Makefile b/drivers/hv/Makefile
> index a1eec7177c2d..d754bd86ca47 100644
> --- a/drivers/hv/Makefile
> +++ b/drivers/hv/Makefile
> @@ -2,6 +2,7 @@
>  obj-$(CONFIG_HYPERV) += hv_vmbus.o
>  obj-$(CONFIG_HYPERV_UTILS)   += hv_utils.o
>  obj-$(CONFIG_HYPERV_BALLOON) += hv_balloon.o
> +obj-$(CONFIG_HYPERV_TESTING) += hv_debugfs.o

There's an additional complexity here that I failed to describe to
you in my previous comments.  :-(The above line makes the
hv_debugfs code part of the main Linux OS image -- i.e., the
vmlinuz file that gets installed into /boot, such that if hv_debugfs
is built, it is always loaded into the memory of the running system.
That's OK, but we should consider the alternative, which is to
make the hv_debugfs code part of the hv_vmbus module that
is specified a bit further down in the same Makefile.   A module
is installed into /lib/modules//kernel, and
is only loaded into memory on the running system if something
actually references code in the module.  This approach helps avoid
loading code into memory that isn't actually used.

Whether code is built as a separate module or is just built into
the main vmlinuz file is also controlled by the .config file setting.
For example, CONFIG_HYPERV=m says to treat hv_vmbus as a
separate module, while CONFIG_HYPERV=y says to build the
hv_vmbus module directly into the vmlinuz file even though the
Makefile constructs it as a module.

Making hv_debugfs part of the hv_vmbus module is generally better
than just building it into the main vmlinuz because it's best to include
only things that must always be present in the main vmlinuz file.
hv_debugfs doesn't have any reason it needs to always be present.
By comparison, hv_balloon is included in the main vmlinuz, which
might be due to it dealing with memory mgmt and needing to be
in the vmlinuz image, but I'm not sure.

You can make hv_debugfs part of the hv_vmbus module with this line
placed after the line specifying hv_vmbus_y, instead of the line you
currently have:

hv_vmbus-$(CONFIG_HYPERV_TESTING)   += hv_debugfs.o

> +
> +static int hv_debugfs_delay_set(void

Re: [PATCH v4 1/2] drivers: hv: vmbus: Introduce latency testing

2019-08-29 Thread kbuild test robot 
Hi Branden,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.3-rc6 next-20190829]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:
https://github.com/0day-ci/linux/commits/Branden-Bonaby/drivers-hv-vmbus-Introduce-latency-testing/20190830-032123
config: i386-allmodconfig (attached as .config)
compiler: gcc-7 (Debian 7.4.0-11) 7.4.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot 

All errors (new ones prefixed by >>):

>> ERROR: "hv_debug_add_dev_dir" [drivers/hv/hv_vmbus.ko] undefined!
>> ERROR: "hv_debug_init" [drivers/hv/hv_vmbus.ko] undefined!
>> ERROR: "hv_debug_delay_test" [drivers/hv/hv_vmbus.ko] undefined!
>> ERROR: "hv_debug_rm_all_dir" [drivers/hv/hv_vmbus.ko] undefined!
>> ERROR: "hv_debug_rm_dev_dir" [drivers/hv/hv_vmbus.ko] undefined!

---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all   Intel Corporation


.config.gz
Description: application/gzip

[PATCH v4 1/2] drivers: hv: vmbus: Introduce latency testing

2019-08-28 Thread Branden Bonaby 
Introduce user specified latency in the packet reception path
By exposing the test parameters as part of the debugfs channel
attributes. We will control the testing state via these attributes.

Signed-off-by: Branden Bonaby 
---
changes in v4:
 - Combined v3 patch 2 into this patch, and changed the
   commit description to reflect this.

 - Moved debugfs code from "vmbus_drv.c" that was in
   previous v3 patch 2, into a new file "debugfs.c" in
   drivers/hv.

 - Updated the Makefile to compile "debugfs.c" if
   CONFIG_HYPERV_TESTING is enabled

 - As per Michael's comments, added empty implementations
   of the new functions, so the compiler will not generate
   code when CONFIG_HYPERV_TESTING is not enabled.

 - Added microseconds into description for files in
   Documentation/ABI/testing/debugfs-hyperv.

Changes in v2:
 - Add #ifdef in Kconfig file so test code will not interfere
   with non-test code.
 - Move test code functions for delay to hyperv_vmbus header
   file.
 - Wrap test code under #ifdef statement.

 Documentation/ABI/testing/debugfs-hyperv |  23 +++
 MAINTAINERS  |   1 +
 drivers/hv/Kconfig   |   7 +
 drivers/hv/Makefile  |   1 +
 drivers/hv/connection.c  |   1 +
 drivers/hv/hv_debugfs.c  | 187 +++
 drivers/hv/hyperv_vmbus.h|  31 
 drivers/hv/ring_buffer.c |   2 +
 drivers/hv/vmbus_drv.c   |   6 +
 include/linux/hyperv.h   |  19 +++
 10 files changed, 278 insertions(+)
 create mode 100644 Documentation/ABI/testing/debugfs-hyperv
 create mode 100644 drivers/hv/hv_debugfs.c

diff --git a/Documentation/ABI/testing/debugfs-hyperv 
b/Documentation/ABI/testing/debugfs-hyperv
new file mode 100644
index ..0903e6427a2d
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-hyperv
@@ -0,0 +1,23 @@
+What:   /sys/kernel/debug/hyperv//fuzz_test_state
+Date:   August 2019
+KernelVersion:  5.3
+Contact:Branden Bonaby 
+Description:Fuzz testing status of a vmbus device, whether its in an ON
+state or a OFF state
+Users:  Debugging tools
+
+What:   
/sys/kernel/debug/hyperv//delay/fuzz_test_buffer_interrupt_delay
+Date:   August 2019
+KernelVersion:  5.3
+Contact:Branden Bonaby 
+Description:Fuzz testing buffer interrupt delay value between 0 - 1000
+microseconds (inclusive).
+Users:  Debugging tools
+
+What:   /sys/kernel/debug/hyperv//delay/fuzz_test_message_delay
+Date:   August 2019
+KernelVersion:  5.3
+Contact:Branden Bonaby 
+Description:Fuzz testing message delay value between 0 - 1000 microseconds
+(inclusive).
+Users:  Debugging tools
diff --git a/MAINTAINERS b/MAINTAINERS
index b1bc9c87838b..6931a4eeaac0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7460,6 +7460,7 @@ F:include/uapi/linux/hyperv.h
 F: include/asm-generic/mshyperv.h
 F: tools/hv/
 F: Documentation/ABI/stable/sysfs-bus-vmbus
+F: Documentation/ABI/testing/debugfs-hyperv
 
 HYPERBUS SUPPORT
 M: Vignesh Raghavendra 
diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index 9a59957922d4..d97437ba0626 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -29,4 +29,11 @@ config HYPERV_BALLOON
help
  Select this option to enable Hyper-V Balloon driver.
 
+config HYPERV_TESTING
+bool "Hyper-V testing"
+default n
+depends on HYPERV && DEBUG_FS
+help
+  Select this option to enable Hyper-V vmbus testing.
+
 endmenu
diff --git a/drivers/hv/Makefile b/drivers/hv/Makefile
index a1eec7177c2d..d754bd86ca47 100644
--- a/drivers/hv/Makefile
+++ b/drivers/hv/Makefile
@@ -2,6 +2,7 @@
 obj-$(CONFIG_HYPERV)   += hv_vmbus.o
 obj-$(CONFIG_HYPERV_UTILS) += hv_utils.o
 obj-$(CONFIG_HYPERV_BALLOON)   += hv_balloon.o
+obj-$(CONFIG_HYPERV_TESTING)   += hv_debugfs.o
 
 CFLAGS_hv_trace.o = -I$(src)
 CFLAGS_hv_balloon.o = -I$(src)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 09829e15d4a0..4d4d40832846 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -357,6 +357,7 @@ void vmbus_on_event(unsigned long data)
 
trace_vmbus_on_event(channel);
 
+   hv_debug_delay_test(channel, INTERRUPT_DELAY);
do {
void (*callback_fn)(void *);
 
diff --git a/drivers/hv/hv_debugfs.c b/drivers/hv/hv_debugfs.c
new file mode 100644
index ..7a3f1ce71ffa
--- /dev/null
+++ b/drivers/hv/hv_debugfs.c
@@ -0,0 +1,187 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Authors:
+ *   Branden Bonaby 
+ */
+
+#include 
+#include 
+#include 
+#include 
+
+#include "hyperv_vmbus.h"
+
+struct dentry *hv_debug_root;
+
+static int hv_debugfs_delay_get(void *data, u64 *val)
+{
+   *val = *(u32 *)data;
+   return 0;
+}
+
+static int