Messages in this thread Patch in this message | | | Date | Tue, 03 Jan 2006 23:28:36 +0000 | From | Shailabh Nagar <> | Subject | [Patch 3/6] Delay accounting: Sync block I/O delays |
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Changes since 12/7/05
- removed __attribute((unused)) qualifiers from timespec vars (dave hansen) - use existing timestamping function do_posix_clock_monotonic_gettime() (jay lan)
Changes since 11/14/05
- use nanosecond resolution, adjusted wall clock time for timestamps instead of sched_clock (akpm, andi, marcelo) - collect stats only if delay accounting enabled (parag) - stats collected for delays in all userspace-initiated block I/O including fsync/fdatasync but not counting waits for async block io events.
11/14/05: First post
delayacct-blkio.patch
Record time spent by a task waiting for completion of userspace initiated synchronous block I/O. This can help determine the right I/O priority for the task.
Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
fs/buffer.c | 6 ++++++ fs/read_write.c | 10 +++++++++- include/linux/delayacct.h | 4 ++++ include/linux/sched.h | 2 ++ kernel/delayacct.c | 16 ++++++++++++++++ mm/filemap.c | 10 +++++++++- mm/memory.c | 17 +++++++++++++++-- 7 files changed, 61 insertions(+), 4 deletions(-)
Index: linux-2.6.15-rc7/include/linux/sched.h =================================================================== --- linux-2.6.15-rc7.orig/include/linux/sched.h +++ linux-2.6.15-rc7/include/linux/sched.h @@ -546,6 +546,8 @@ struct task_delay_info { spinlock_t lock;
/* Add stats in pairs: uint64_t delay, uint32_t count */ + uint64_t blkio_delay; /* wait for sync block io completion */ + uint32_t blkio_count; }; #endif
Index: linux-2.6.15-rc7/fs/read_write.c =================================================================== --- linux-2.6.15-rc7.orig/fs/read_write.c +++ linux-2.6.15-rc7/fs/read_write.c @@ -14,6 +14,8 @@ #include <linux/security.h> #include <linux/module.h> #include <linux/syscalls.h> +#include <linux/time.h> +#include <linux/delayacct.h>
#include <asm/uaccess.h> #include <asm/unistd.h> @@ -224,8 +226,14 @@ ssize_t do_sync_read(struct file *filp, (ret = filp->f_op->aio_read(&kiocb, buf, len, kiocb.ki_pos))) wait_on_retry_sync_kiocb(&kiocb);
- if (-EIOCBQUEUED == ret) + if (-EIOCBQUEUED == ret) { + struct timespec start, end; + + do_posix_clock_monotonic_gettime(&start); ret = wait_on_sync_kiocb(&kiocb); + do_posix_clock_monotonic_gettime(&end); + delayacct_blkio(&start, &end); + } *ppos = kiocb.ki_pos; return ret; } Index: linux-2.6.15-rc7/mm/filemap.c =================================================================== --- linux-2.6.15-rc7.orig/mm/filemap.c +++ linux-2.6.15-rc7/mm/filemap.c @@ -28,6 +28,8 @@ #include <linux/blkdev.h> #include <linux/security.h> #include <linux/syscalls.h> +#include <linux/time.h> +#include <linux/delayacct.h> #include "filemap.h" /* * FIXME: remove all knowledge of the buffer layer from the core VM @@ -1062,8 +1064,14 @@ generic_file_read(struct file *filp, cha
init_sync_kiocb(&kiocb, filp); ret = __generic_file_aio_read(&kiocb, &local_iov, 1, ppos); - if (-EIOCBQUEUED == ret) + if (-EIOCBQUEUED == ret) { + struct timespec start, end; + + do_posix_clock_monotonic_gettime(&start); ret = wait_on_sync_kiocb(&kiocb); + do_posix_clock_monotonic_gettime(&end); + delayacct_blkio(&start, &end); + } return ret; }
Index: linux-2.6.15-rc7/mm/memory.c =================================================================== --- linux-2.6.15-rc7.orig/mm/memory.c +++ linux-2.6.15-rc7/mm/memory.c @@ -48,6 +48,8 @@ #include <linux/rmap.h> #include <linux/module.h> #include <linux/init.h> +#include <linux/time.h> +#include <linux/delayacct.h>
#include <asm/pgalloc.h> #include <asm/uaccess.h> @@ -2170,11 +2172,22 @@ static inline int handle_pte_fault(struc old_entry = entry = *pte; if (!pte_present(entry)) { if (pte_none(entry)) { + int ret; + struct timespec start, end; + if (!vma->vm_ops || !vma->vm_ops->nopage) return do_anonymous_page(mm, vma, address, pte, pmd, write_access); - return do_no_page(mm, vma, address, - pte, pmd, write_access); + + if (vma->vm_file) + do_posix_clock_monotonic_gettime(&start); + ret = do_no_page(mm, vma, address, + pte, pmd, write_access); + if (vma->vm_file) { + do_posix_clock_monotonic_gettime(&end); + delayacct_blkio(&start, &end); + } + return ret; } if (pte_file(entry)) return do_file_page(mm, vma, address, Index: linux-2.6.15-rc7/fs/buffer.c =================================================================== --- linux-2.6.15-rc7.orig/fs/buffer.c +++ linux-2.6.15-rc7/fs/buffer.c @@ -41,6 +41,8 @@ #include <linux/bitops.h> #include <linux/mpage.h> #include <linux/bit_spinlock.h> +#include <linux/time.h> +#include <linux/delayacct.h>
static int fsync_buffers_list(spinlock_t *lock, struct list_head *list); static void invalidate_bh_lrus(void); @@ -337,6 +339,7 @@ static long do_fsync(unsigned int fd, in struct file * file; struct address_space *mapping; int ret, err; + struct timespec start, end;
ret = -EBADF; file = fget(fd); @@ -349,6 +352,7 @@ static long do_fsync(unsigned int fd, in goto out_putf; }
+ do_posix_clock_monotonic_gettime(&start); mapping = file->f_mapping;
current->flags |= PF_SYNCWRITE; @@ -371,6 +375,8 @@ static long do_fsync(unsigned int fd, in out_putf: fput(file); out: + do_posix_clock_monotonic_gettime(&end); + delayacct_blkio(&start, &end); return ret; }
Index: linux-2.6.15-rc7/include/linux/delayacct.h =================================================================== --- linux-2.6.15-rc7.orig/include/linux/delayacct.h +++ linux-2.6.15-rc7/include/linux/delayacct.h @@ -19,8 +19,12 @@ #ifdef CONFIG_TASK_DELAY_ACCT extern int delayacct_on; /* Delay accounting turned on/off */ extern void delayacct_tsk_init(struct task_struct *tsk); +extern void delayacct_blkio(struct timespec *start, struct timespec *end); #else static inline void delayacct_tsk_init(struct task_struct *tsk) {} +static inline void delayacct_blkio(struct timespec *start, struct timespec *end) +{} + #endif /* CONFIG_TASK_DELAY_ACCT */ #endif /* _LINUX_TASKDELAYS_H */ Index: linux-2.6.15-rc7/kernel/delayacct.c =================================================================== --- linux-2.6.15-rc7.orig/kernel/delayacct.c +++ linux-2.6.15-rc7/kernel/delayacct.c @@ -12,6 +12,7 @@ */
#include <linux/sched.h> +#include <linux/time.h>
int delayacct_on=1; /* Delay accounting turned on/off */
@@ -34,3 +35,18 @@ static int __init delayacct_init(void) return 0; } core_initcall(delayacct_init); + +inline void delayacct_blkio(struct timespec *start, struct timespec *end) +{ + unsigned long long delay; + + if (!delayacct_on) + return; + + delay = timespec_diff_ns(start, end); + + spin_lock(¤t->delays.lock); + current->delays.blkio_delay += delay; + current->delays.blkio_count++; + spin_unlock(¤t->delays.lock); +} - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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