Changeset 77140 in vbox for trunk/src/VBox/Additions/linux/sharedfolders/utils.c

Timestamp:

Feb 1, 2019 7:38:26 PM (6 years ago)

Author:

vboxsync

Message:

linux/vboxsf: Set st_blksize to 1MB for files and 16KB for directories, rather than the 4KB we used to. With 1MB I see close to optimal sequential read performance here, 15x better than with 4KB. bugref:9172

File:

• trunk/src/VBox/Additions/linux/sharedfolders/utils.c (modified) (1 diff)

trunk/src/VBox/Additions/linux/sharedfolders/utils.c

@@ -355 +355 @@
 
         generic_fillattr(dentry->d_inode, kstat);
+
+        /*
+         * FsPerf shows the following numbers for sequential file reads:
+         *   4096 KB = 2254 MB/s
+         *   2048 KB = 2368 MB/s
+         *   1024 KB = 2208 MB/s
+         *    512 KB = 1908 MB/s
+         *    256 KB = 1625 MB/s
+         *    128 KB = 1413 MB/s
+         *     64 KB = 1152 MB/s
+         *     32 KB =  726 MB/s
+         *      4 KB =  145 MB/s
+         */
+        if (S_ISREG(kstat->mode))
+                kstat->blksize = _1M;
+        else if (S_ISDIR(kstat->mode))
+                /** @todo this may need more tuning after we rewrite the directory handling. */
+                kstat->blksize = _16K;
         return 0;
 }