diff options
author | David Daney <ddaney@caviumnetworks.com> | 2010-02-17 00:26:35 +0100 |
---|---|---|
committer | Ralf Baechle <ralf@linux-mips.org> | 2010-02-27 12:53:42 +0100 |
commit | bba90760582d2563b28a4738fb785185a59e9e71 (patch) | |
tree | b1efda424d8ab0ef24220ce4da484819d749e2b2 /arch/mips/kernel/spinlock_test.c | |
parent | MIPS: Optimize spinlocks. (diff) | |
download | linux-bba90760582d2563b28a4738fb785185a59e9e71.tar.xz linux-bba90760582d2563b28a4738fb785185a59e9e71.zip |
MIPS: Crazy spinlock speed test.
This is just a test program for raw_spinlocks. The main reason I
wrote it is to validate my spinlock changes that I sent in a previous
patch.
To use it enable CONFIG_DEBUG_FS and CONFIG_SPINLOCK_TEST then at run
time do:
# mount -t debugfs none /sys/kernel/debug/
# cat /sys/kernel/debug/mips/spin_single
# cat /sys/kernel/debug/mips/spin_multi
On my 600MHz octeon cn5860 (16 CPUs) I get
spin_single spin_multi
base 106885 247941
spinlock_patch 75194 219465
This shows that for uncontended locks the spinlock patch gives 41%
improvement and for contended locks 12% improvement (1/time).
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/969/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to '')
-rw-r--r-- | arch/mips/kernel/spinlock_test.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/arch/mips/kernel/spinlock_test.c b/arch/mips/kernel/spinlock_test.c new file mode 100644 index 000000000000..da61134dfc53 --- /dev/null +++ b/arch/mips/kernel/spinlock_test.c @@ -0,0 +1,141 @@ +#include <linux/init.h> +#include <linux/kthread.h> +#include <linux/hrtimer.h> +#include <linux/fs.h> +#include <linux/debugfs.h> +#include <linux/module.h> +#include <linux/spinlock.h> + + +static int ss_get(void *data, u64 *val) +{ + ktime_t start, finish; + int loops; + int cont; + DEFINE_RAW_SPINLOCK(ss_spin); + + loops = 1000000; + cont = 1; + + start = ktime_get(); + + while (cont) { + raw_spin_lock(&ss_spin); + loops--; + if (loops == 0) + cont = 0; + raw_spin_unlock(&ss_spin); + } + + finish = ktime_get(); + + *val = ktime_us_delta(finish, start); + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(fops_ss, ss_get, NULL, "%llu\n"); + + + +struct spin_multi_state { + raw_spinlock_t lock; + atomic_t start_wait; + atomic_t enter_wait; + atomic_t exit_wait; + int loops; +}; + +struct spin_multi_per_thread { + struct spin_multi_state *state; + ktime_t start; +}; + +static int multi_other(void *data) +{ + int loops; + int cont; + struct spin_multi_per_thread *pt = data; + struct spin_multi_state *s = pt->state; + + loops = s->loops; + cont = 1; + + atomic_dec(&s->enter_wait); + + while (atomic_read(&s->enter_wait)) + ; /* spin */ + + pt->start = ktime_get(); + + atomic_dec(&s->start_wait); + + while (atomic_read(&s->start_wait)) + ; /* spin */ + + while (cont) { + raw_spin_lock(&s->lock); + loops--; + if (loops == 0) + cont = 0; + raw_spin_unlock(&s->lock); + } + + atomic_dec(&s->exit_wait); + while (atomic_read(&s->exit_wait)) + ; /* spin */ + return 0; +} + +static int multi_get(void *data, u64 *val) +{ + ktime_t finish; + struct spin_multi_state ms; + struct spin_multi_per_thread t1, t2; + + ms.lock = __RAW_SPIN_LOCK_UNLOCKED("multi_get"); + ms.loops = 1000000; + + atomic_set(&ms.start_wait, 2); + atomic_set(&ms.enter_wait, 2); + atomic_set(&ms.exit_wait, 2); + t1.state = &ms; + t2.state = &ms; + + kthread_run(multi_other, &t2, "multi_get"); + + multi_other(&t1); + + finish = ktime_get(); + + *val = ktime_us_delta(finish, t1.start); + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(fops_multi, multi_get, NULL, "%llu\n"); + + +extern struct dentry *mips_debugfs_dir; +static int __init spinlock_test(void) +{ + struct dentry *d; + + if (!mips_debugfs_dir) + return -ENODEV; + + d = debugfs_create_file("spin_single", S_IRUGO, + mips_debugfs_dir, NULL, + &fops_ss); + if (!d) + return -ENOMEM; + + d = debugfs_create_file("spin_multi", S_IRUGO, + mips_debugfs_dir, NULL, + &fops_multi); + if (!d) + return -ENOMEM; + + return 0; +} +device_initcall(spinlock_test); |