Re: [PATCH tip/core/rcu 06/45] torture: Intensify locking test
On Wed, May 07, 2014 at 02:20:15PM -0700, j...@joshtriplett.org wrote:
> On Mon, Apr 28, 2014 at 05:24:54PM -0700, Paul E. McKenney wrote:
> > From: "Paul E. McKenney"
> >
> > The current lock_torture_writer() spends too much time sleeping and not
> > enough time hammering locks, as in an eight-CPU test will often only be
> > utilizing a CPU or two. This commit therefore makes lock_torture_writer()
> > sleep less and hammer more.
> >
> > Signed-off-by: Paul E. McKenney
> > ---
> > kernel/locking/locktorture.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
> > index f26b1a18e34e..b0d3e3c50672 100644
> > --- a/kernel/locking/locktorture.c
> > +++ b/kernel/locking/locktorture.c
> > @@ -219,7 +219,8 @@ static int lock_torture_writer(void *arg)
> > set_user_nice(current, 19);
> >
> > do {
> > - schedule_timeout_uninterruptible(1);
> > + if ((torture_random() & 0xf) == 0)
> > + schedule_timeout_uninterruptible(1);
>
> That's a one-in-1048576 chance of sleeping for a jiffy; is that frequent
> enough to even bother sleeping at all?
On large systems, maybe not. Smallish systems should be able to get
through that loop a million times in a few hundreds of milliseconds,
though. So longer term a smarter approach might be needed, but this
should be a good start.
Thanx, Paul
> > cur_ops->writelock();
> > if (WARN_ON_ONCE(lock_is_write_held))
> > lwsp->n_write_lock_fail++;
> > --
> > 1.8.1.5
> >
>
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Re: [PATCH tip/core/rcu 06/45] torture: Intensify locking test
On Mon, Apr 28, 2014 at 05:24:54PM -0700, Paul E. McKenney wrote:
> From: "Paul E. McKenney"
>
> The current lock_torture_writer() spends too much time sleeping and not
> enough time hammering locks, as in an eight-CPU test will often only be
> utilizing a CPU or two. This commit therefore makes lock_torture_writer()
> sleep less and hammer more.
>
> Signed-off-by: Paul E. McKenney
> ---
> kernel/locking/locktorture.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
> index f26b1a18e34e..b0d3e3c50672 100644
> --- a/kernel/locking/locktorture.c
> +++ b/kernel/locking/locktorture.c
> @@ -219,7 +219,8 @@ static int lock_torture_writer(void *arg)
> set_user_nice(current, 19);
>
> do {
> - schedule_timeout_uninterruptible(1);
> + if ((torture_random() & 0xf) == 0)
> + schedule_timeout_uninterruptible(1);
That's a one-in-1048576 chance of sleeping for a jiffy; is that frequent
enough to even bother sleeping at all?
> cur_ops->writelock();
> if (WARN_ON_ONCE(lock_is_write_held))
> lwsp->n_write_lock_fail++;
> --
> 1.8.1.5
>
--
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Re: [PATCH tip/core/rcu 06/45] torture: Intensify locking test
On Mon, Apr 28, 2014 at 05:24:54PM -0700, Paul E. McKenney wrote:
From: Paul E. McKenney paul...@linux.vnet.ibm.com
The current lock_torture_writer() spends too much time sleeping and not
enough time hammering locks, as in an eight-CPU test will often only be
utilizing a CPU or two. This commit therefore makes lock_torture_writer()
sleep less and hammer more.
Signed-off-by: Paul E. McKenney paul...@linux.vnet.ibm.com
---
kernel/locking/locktorture.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index f26b1a18e34e..b0d3e3c50672 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -219,7 +219,8 @@ static int lock_torture_writer(void *arg)
set_user_nice(current, 19);
do {
- schedule_timeout_uninterruptible(1);
+ if ((torture_random(rand) 0xf) == 0)
+ schedule_timeout_uninterruptible(1);
That's a one-in-1048576 chance of sleeping for a jiffy; is that frequent
enough to even bother sleeping at all?
cur_ops-writelock();
if (WARN_ON_ONCE(lock_is_write_held))
lwsp-n_write_lock_fail++;
--
1.8.1.5
--
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the body of a message to majord...@vger.kernel.org
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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH tip/core/rcu 06/45] torture: Intensify locking test
On Wed, May 07, 2014 at 02:20:15PM -0700, j...@joshtriplett.org wrote:
On Mon, Apr 28, 2014 at 05:24:54PM -0700, Paul E. McKenney wrote:
From: Paul E. McKenney paul...@linux.vnet.ibm.com
The current lock_torture_writer() spends too much time sleeping and not
enough time hammering locks, as in an eight-CPU test will often only be
utilizing a CPU or two. This commit therefore makes lock_torture_writer()
sleep less and hammer more.
Signed-off-by: Paul E. McKenney paul...@linux.vnet.ibm.com
---
kernel/locking/locktorture.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index f26b1a18e34e..b0d3e3c50672 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -219,7 +219,8 @@ static int lock_torture_writer(void *arg)
set_user_nice(current, 19);
do {
- schedule_timeout_uninterruptible(1);
+ if ((torture_random(rand) 0xf) == 0)
+ schedule_timeout_uninterruptible(1);
That's a one-in-1048576 chance of sleeping for a jiffy; is that frequent
enough to even bother sleeping at all?
On large systems, maybe not. Smallish systems should be able to get
through that loop a million times in a few hundreds of milliseconds,
though. So longer term a smarter approach might be needed, but this
should be a good start.
Thanx, Paul
cur_ops-writelock();
if (WARN_ON_ONCE(lock_is_write_held))
lwsp-n_write_lock_fail++;
--
1.8.1.5
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH tip/core/rcu 06/45] torture: Intensify locking test
From: "Paul E. McKenney"
The current lock_torture_writer() spends too much time sleeping and not
enough time hammering locks, as in an eight-CPU test will often only be
utilizing a CPU or two. This commit therefore makes lock_torture_writer()
sleep less and hammer more.
Signed-off-by: Paul E. McKenney
---
kernel/locking/locktorture.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index f26b1a18e34e..b0d3e3c50672 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -219,7 +219,8 @@ static int lock_torture_writer(void *arg)
set_user_nice(current, 19);
do {
- schedule_timeout_uninterruptible(1);
+ if ((torture_random() & 0xf) == 0)
+ schedule_timeout_uninterruptible(1);
cur_ops->writelock();
if (WARN_ON_ONCE(lock_is_write_held))
lwsp->n_write_lock_fail++;
--
1.8.1.5
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH tip/core/rcu 06/45] torture: Intensify locking test
From: Paul E. McKenney paul...@linux.vnet.ibm.com
The current lock_torture_writer() spends too much time sleeping and not
enough time hammering locks, as in an eight-CPU test will often only be
utilizing a CPU or two. This commit therefore makes lock_torture_writer()
sleep less and hammer more.
Signed-off-by: Paul E. McKenney paul...@linux.vnet.ibm.com
---
kernel/locking/locktorture.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index f26b1a18e34e..b0d3e3c50672 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -219,7 +219,8 @@ static int lock_torture_writer(void *arg)
set_user_nice(current, 19);
do {
- schedule_timeout_uninterruptible(1);
+ if ((torture_random(rand) 0xf) == 0)
+ schedule_timeout_uninterruptible(1);
cur_ops-writelock();
if (WARN_ON_ONCE(lock_is_write_held))
lwsp-n_write_lock_fail++;
--
1.8.1.5
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
