Index: lib/libstand/read.c
===================================================================
--- lib/libstand/read.c	(revision 288668)
+++ lib/libstand/read.c	(working copy)
@@ -78,8 +78,11 @@
     }
     if (f->f_flags & F_RAW) {
 	twiddle(4);
-	errno = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-					btodb(f->f_offset), bcount, dest, &resid);
+	int flag = F_READ;
+	if (bcount >1024)
+		flag |= F_NOBUF;	/* avoid bcache trashing */
+	errno = (f->f_dev->dv_strategy)(f->f_devdata, flag, btodb(f->f_offset),
+	    bcount, dest, &resid);
 	if (errno)
 	    return (-1);
 	f->f_offset += resid;
Index: lib/libstand/stand.h
===================================================================
--- lib/libstand/stand.h	(revision 288668)
+++ lib/libstand/stand.h	(working copy)
@@ -174,7 +174,10 @@
 #define	F_READ		0x0001	/* file opened for reading */
 #define	F_WRITE		0x0002	/* file opened for writing */
 #define	F_RAW		0x0004	/* raw device open - no file system */
-#define F_NODEV		0x0008	/* network open - no device */
+#define	F_NODEV		0x0008	/* network open - no device */
+#define	F_GZIP		0x0010  /* file is compressed by gzip */
+#define	F_BZIP		0x0020	/* file is compressed by bzip */
+#define	F_NOBUF		0x0040	/* skip bcache */
 
 #define isascii(c)	(((c) & ~0x7F) == 0)
 
Index: lib/libstand/ufs.c
===================================================================
--- lib/libstand/ufs.c	(revision 288668)
+++ lib/libstand/ufs.c	(working copy)
@@ -407,8 +407,9 @@
 			fp->f_buf_size = block_size;
 		} else {
 			twiddle(4);
-			rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-				fsbtodb(fs, disk_block),
+			/* disable double buffering for speed */
+			rc = (f->f_dev->dv_strategy)(f->f_devdata,
+				F_READ|F_NOBUF, fsbtodb(fs, disk_block),
 				block_size, fp->f_buf, &fp->f_buf_size);
 			if (rc)
 				return (rc);
Index: sys/boot/common/bcache.c
===================================================================
--- sys/boot/common/bcache.c	(revision 288668)
+++ sys/boot/common/bcache.c	(working copy)
@@ -238,8 +238,10 @@
     }
 
     /* bypass large requests, or when the cache is inactive */
-    if ((bcache_data == NULL) || ((size * 2 / bcache_blksize) > bcache_nblks)) {
+    if ((bcache_data == NULL) || (rw & F_NOBUF) ||
+	((size * 2 / bcache_blksize) > bcache_nblks)) {
 	DEBUG("bypass %d from %d", size / bcache_blksize, blk);
+	rw &= ~F_NOBUF;
 	bcache_bypasses++;
 	return(dd->dv_strategy(dd->dv_devdata, rw, blk, size, buf, rsize));
     }