Adding upstream version 9.1.upstream/9.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 82 insertions, 0 deletions

diff --git a/src/ioblksize.h b/src/ioblksize.h
new file mode 100644
index 0000000..8bd18ba
--- /dev/null
+++ b/src/ioblksize.h
@@ -0,0 +1,82 @@
+/* I/O block size definitions for coreutils
+   Copyright (C) 1989-2022 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Include this file _after_ system headers if possible.  */
+
+/* sys/stat.h and minmax.h will already have been included by system.h. */
+#include "idx.h"
+#include "stat-size.h"
+
+
+/* As of May 2014, 128KiB is determined to be the minimium
+   blksize to best minimize system call overhead.
+   This can be tested with this script:
+
+   for i in $(seq 0 10); do
+     bs=$((1024*2**$i))
+     printf "%7s=" $bs
+     timeout --foreground -sINT 2 \
+       dd bs=$bs if=/dev/zero of=/dev/null 2>&1 \
+         | sed -n 's/.* \([0-9.]* [GM]B\/s\)/\1/p'
+   done
+
+   With the results shown for these systems:
+   system #1: 1.7GHz pentium-m with 400MHz DDR2 RAM, arch=i686
+   system #2: 2.1GHz i3-2310M with 1333MHz DDR3 RAM, arch=x86_64
+   system #3: 3.2GHz i7-970 with 1333MHz DDR3, arch=x86_64
+   system #4: 2.20GHz Xeon E5-2660 with 1333MHz DDR3, arch=x86_64
+   system #5: 2.30GHz i7-3615QM with 1600MHz DDR3, arch=x86_64
+   system #6: 1.30GHz i5-4250U with 1-channel 1600MHz DDR3, arch=x86_64
+   system #7: 3.55GHz IBM,8231-E2B with 1066MHz DDR3, POWER7 revision 2.1
+
+                per-system transfer rate (GB/s)
+   blksize   #1    #2    #3    #4    #5    #6    #7
+   ------------------------------------------------------------------------
+      1024  .73   1.7   2.6   .64   1.0   2.5   1.3
+      2048  1.3   3.0   4.4   1.2   2.0   4.4   2.5
+      4096  2.4   5.1   6.5   2.3   3.7   7.4   4.8
+      8192  3.5   7.3   8.5   4.0   6.0  10.4   9.2
+     16384  3.9   9.4  10.1   6.3   8.3  13.3  16.8
+     32768  5.2   9.9  11.1   8.1  10.7  13.2  28.0
+     65536  5.3  11.2  12.0  10.6  12.8  16.1  41.4
+    131072  5.5  11.8  12.3  12.1  14.0  16.7  54.8
+    262144  5.7  11.6  12.5  12.3  14.7  16.4  40.0
+    524288  5.7  11.4  12.5  12.1  14.7  15.5  34.5
+   1048576  5.8  11.4  12.6  12.2  14.9  15.7  36.5
+
+
+   Note that this is to minimize system call overhead.
+   Other values may be appropriate to minimize file system
+   overhead.  For example on my current GNU/Linux system
+   the readahead setting is 128KiB which was read using:
+
+   file="."
+   device=$(df --output=source --local "$file" | tail -n1)
+   echo $(( $(blockdev --getra $device) * 512 ))
+
+   However there isn't a portable way to get the above.
+   In the future we could use the above method if available
+   and default to io_blksize() if not.
+ */
+enum { IO_BUFSIZE = 128 * 1024 };
+static inline idx_t
+io_blksize (struct stat sb)
+{
+  /* Don’t go above the largest power of two that fits in idx_t and size_t,
+     as that is asking for trouble.  */
+  return MIN (MIN (IDX_MAX, SIZE_MAX) / 2 + 1,
+              MAX (IO_BUFSIZE, ST_BLKSIZE (sb)));
+}