Author: tmunro Date: Sun Jun 21 08:51:24 2020 New Revision: 362460 URL: https://svnweb.freebsd.org/changeset/base/362460
Log: vfs: track sequential reads and writes separately For software like PostgreSQL and SQLite that sometimes reads sequentially while also writing sequentially some distance behind with interleaved syscalls on the same fd, performance is better on UFS if we do sequential access heuristics separately for reads and writes. Patch originally by Andrew Gierth in 2008, updated and proposed by me with his permission. Reviewed by: mjg, kib, tmunro Approved by: mjg (mentor) Obtained from: Andrew Gierth <and...@tao11.riddles.org.uk> Differential Revision: https://reviews.freebsd.org/D25024 Modified: head/sys/compat/cloudabi/cloudabi_file.c head/sys/fs/devfs/devfs_vnops.c head/sys/kern/kern_descrip.c head/sys/kern/vfs_syscalls.c head/sys/kern/vfs_vnops.c head/sys/sys/file.h Modified: head/sys/compat/cloudabi/cloudabi_file.c ============================================================================== --- head/sys/compat/cloudabi/cloudabi_file.c Sun Jun 21 04:59:02 2020 (r362459) +++ head/sys/compat/cloudabi/cloudabi_file.c Sun Jun 21 08:51:24 2020 (r362460) @@ -287,7 +287,8 @@ cloudabi_sys_file_open(struct thread *td, /* Install vnode operations if no custom operations are provided. */ if (fp->f_ops == &badfileops) { - fp->f_seqcount = 1; + fp->f_seqcount[UIO_READ] = 1; + fp->f_seqcount[UIO_WRITE] = 1; finit(fp, (fflags & FMASK) | (fp->f_flag & FHASLOCK), DTYPE_VNODE, vp, &vnops); } Modified: head/sys/fs/devfs/devfs_vnops.c ============================================================================== --- head/sys/fs/devfs/devfs_vnops.c Sun Jun 21 04:59:02 2020 (r362459) +++ head/sys/fs/devfs/devfs_vnops.c Sun Jun 21 08:51:24 2020 (r362460) @@ -1305,7 +1305,7 @@ devfs_read_f(struct file *fp, struct uio *uio, struct td->td_fpop = fpop; dev_relthread(dev, ref); - foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF); + foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF_R); return (error); } @@ -1802,7 +1802,7 @@ devfs_write_f(struct file *fp, struct uio *uio, struct td->td_fpop = fpop; dev_relthread(dev, ref); - foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF); + foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF_W); return (error); } Modified: head/sys/kern/kern_descrip.c ============================================================================== --- head/sys/kern/kern_descrip.c Sun Jun 21 04:59:02 2020 (r362459) +++ head/sys/kern/kern_descrip.c Sun Jun 21 08:51:24 2020 (r362460) @@ -795,7 +795,7 @@ kern_fcntl(struct thread *td, int fd, int cmd, intptr_ if (arg >= 0) { bsize = fp->f_vnode->v_mount->mnt_stat.f_iosize; arg = MIN(arg, INT_MAX - bsize + 1); - fp->f_seqcount = MIN(IO_SEQMAX, + fp->f_seqcount[UIO_READ] = MIN(IO_SEQMAX, (arg + bsize - 1) / bsize); atomic_set_int(&fp->f_flag, FRDAHEAD); } else { Modified: head/sys/kern/vfs_syscalls.c ============================================================================== --- head/sys/kern/vfs_syscalls.c Sun Jun 21 04:59:02 2020 (r362459) +++ head/sys/kern/vfs_syscalls.c Sun Jun 21 08:51:24 2020 (r362460) @@ -1124,7 +1124,8 @@ kern_openat(struct thread *td, int fd, const char *pat */ if (fp->f_ops == &badfileops) { KASSERT(vp->v_type != VFIFO, ("Unexpected fifo.")); - fp->f_seqcount = 1; + fp->f_seqcount[UIO_READ] = 1; + fp->f_seqcount[UIO_WRITE] = 1; finit(fp, (flags & FMASK) | (fp->f_flag & FHASLOCK), DTYPE_VNODE, vp, &vnops); } @@ -4442,7 +4443,8 @@ sys_fhopen(struct thread *td, struct fhopen_args *uap) td->td_dupfd = 0; #endif fp->f_vnode = vp; - fp->f_seqcount = 1; + fp->f_seqcount[UIO_READ] = 1; + fp->f_seqcount[UIO_WRITE] = 1; finit(fp, (fmode & FMASK) | (fp->f_flag & FHASLOCK), DTYPE_VNODE, vp, &vnops); VOP_UNLOCK(vp); Modified: head/sys/kern/vfs_vnops.c ============================================================================== --- head/sys/kern/vfs_vnops.c Sun Jun 21 04:59:02 2020 (r362459) +++ head/sys/kern/vfs_vnops.c Sun Jun 21 08:51:24 2020 (r362460) @@ -489,10 +489,13 @@ vn_close(struct vnode *vp, int flags, struct ucred *fi static int sequential_heuristic(struct uio *uio, struct file *fp) { + enum uio_rw rw; ASSERT_VOP_LOCKED(fp->f_vnode, __func__); + + rw = uio->uio_rw; if (fp->f_flag & FRDAHEAD) - return (fp->f_seqcount << IO_SEQSHIFT); + return (fp->f_seqcount[rw] << IO_SEQSHIFT); /* * Offset 0 is handled specially. open() sets f_seqcount to 1 so @@ -501,8 +504,8 @@ sequential_heuristic(struct uio *uio, struct file *fp) * unless previous seeks have reduced f_seqcount to 0, in which * case offset 0 is not special. */ - if ((uio->uio_offset == 0 && fp->f_seqcount > 0) || - uio->uio_offset == fp->f_nextoff) { + if ((uio->uio_offset == 0 && fp->f_seqcount[rw] > 0) || + uio->uio_offset == fp->f_nextoff[rw]) { /* * f_seqcount is in units of fixed-size blocks so that it * depends mainly on the amount of sequential I/O and not @@ -513,20 +516,20 @@ sequential_heuristic(struct uio *uio, struct file *fp) * to any block size used by software. */ if (uio->uio_resid >= IO_SEQMAX * 16384) - fp->f_seqcount = IO_SEQMAX; + fp->f_seqcount[rw] = IO_SEQMAX; else { - fp->f_seqcount += howmany(uio->uio_resid, 16384); - if (fp->f_seqcount > IO_SEQMAX) - fp->f_seqcount = IO_SEQMAX; + fp->f_seqcount[rw] += howmany(uio->uio_resid, 16384); + if (fp->f_seqcount[rw] > IO_SEQMAX) + fp->f_seqcount[rw] = IO_SEQMAX; } - return (fp->f_seqcount << IO_SEQSHIFT); + return (fp->f_seqcount[rw] << IO_SEQSHIFT); } /* Not sequential. Quickly draw-down sequentiality. */ - if (fp->f_seqcount > 1) - fp->f_seqcount = 1; + if (fp->f_seqcount[rw] > 1) + fp->f_seqcount[rw] = 1; else - fp->f_seqcount = 0; + fp->f_seqcount[rw] = 0; return (0); } @@ -734,8 +737,10 @@ foffset_unlock(struct file *fp, off_t val, int flags) if ((flags & FOF_NOUPDATE) == 0) atomic_store_long(&fp->f_offset, val); - if ((flags & FOF_NEXTOFF) != 0) - fp->f_nextoff = val; + if ((flags & FOF_NEXTOFF_R) != 0) + fp->f_nextoff[UIO_READ] = val; + if ((flags & FOF_NEXTOFF_W) != 0) + fp->f_nextoff[UIO_WRITE] = val; if ((flags & FOF_NOLOCK) != 0) return; @@ -788,8 +793,10 @@ foffset_unlock(struct file *fp, off_t val, int flags) mtx_lock(mtxp); if ((flags & FOF_NOUPDATE) == 0) fp->f_offset = val; - if ((flags & FOF_NEXTOFF) != 0) - fp->f_nextoff = val; + if ((flags & FOF_NEXTOFF_R) != 0) + fp->f_nextoff[UIO_READ] = val; + if ((flags & FOF_NEXTOFF_W) != 0) + fp->f_nextoff[UIO_WRITE] = val; if ((flags & FOF_NOLOCK) == 0) { KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, ("Lost FOFFSET_LOCKED")); @@ -878,7 +885,7 @@ vn_read(struct file *fp, struct uio *uio, struct ucred if (error == 0) #endif error = VOP_READ(vp, uio, ioflag, fp->f_cred); - fp->f_nextoff = uio->uio_offset; + fp->f_nextoff[UIO_READ] = uio->uio_offset; VOP_UNLOCK(vp); if (error == 0 && advice == POSIX_FADV_NOREUSE && orig_offset != uio->uio_offset) @@ -953,7 +960,7 @@ vn_write(struct file *fp, struct uio *uio, struct ucre if (error == 0) #endif error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); - fp->f_nextoff = uio->uio_offset; + fp->f_nextoff[UIO_WRITE] = uio->uio_offset; VOP_UNLOCK(vp); if (vp->v_type != VCHR) vn_finished_write(mp); Modified: head/sys/sys/file.h ============================================================================== --- head/sys/sys/file.h Sun Jun 21 04:59:02 2020 (r362459) +++ head/sys/sys/file.h Sun Jun 21 08:51:24 2020 (r362460) @@ -81,7 +81,8 @@ struct ucred; #define FOF_OFFSET 0x01 /* Use the offset in uio argument */ #define FOF_NOLOCK 0x02 /* Do not take FOFFSET_LOCK */ -#define FOF_NEXTOFF 0x04 /* Also update f_nextoff */ +#define FOF_NEXTOFF_R 0x04 /* Also update f_nextoff[UIO_READ] */ +#define FOF_NEXTOFF_W 0x08 /* Also update f_nextoff[UIO_WRITE] */ #define FOF_NOUPDATE 0x10 /* Do not update f_offset */ off_t foffset_lock(struct file *fp, int flags); void foffset_lock_uio(struct file *fp, struct uio *uio, int flags); @@ -187,10 +188,10 @@ struct file { * DTYPE_VNODE specific fields. */ union { - int16_t f_seqcount; /* (a) Count of sequential accesses. */ + int16_t f_seqcount[2]; /* (a) Count of seq. reads and writes. */ int f_pipegen; }; - off_t f_nextoff; /* next expected read/write offset. */ + off_t f_nextoff[2]; /* next expected read/write offset. */ union { struct cdev_privdata *fvn_cdevpriv; /* (d) Private data for the cdev. */ _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
