rmap 15j for 2.4.21-rc6

Well, I did the test with 2.4.21rc6 after patching your script (I got syntax errors):

When I'm using the script as seen in the patch, I'm getting problems with df (it's mostly very lazy, about 20s delay or more), the load is 4, doing an ls on some other directories is extremly slow. Mouse and keyboard are hanging some times.
The write speed shown in xosview was between 1 and 15MB/s. Often the HD LED was on, but no data seemed to be put to the HD.

My system:
AMD Athlon(tm) XP 2000+
512 MB RAM
Chipsatz Apollo KT266/A/333
WDC WD205AA, udma4, 20,5 GB
(multcount = 16 (on),I/O support = 1 (32-bit),
unmaskirq = 1 (on),using_dma = 1 (on),
readahead = 8 (on)
)
reiserfs

Regards,
Andreas Hartmann

@@ -138,7 +138,7 @@
     sleep 1
    fi
  #invoke dd write loops
-   while (( i-- )); do
+   while (( i=`expr $i - 1` )); do
      $TSTINTER _xwrite "$2" $i
      sleep 1
    done

@@ -163,13 +163,13 @@
  #
  _read)
    if [ "$2" = "" ]; then
-     count=100K
+     count=100000
    else
      count=$2
    fi
-   dd if=/dev/zero of=$TEMPFILE$3 bs=4K count=$count
+   dd if=/dev/zero of=$TEMPFILE$3 bs=4096 count=$count
    while (( 1 )); do
-     time dd if=$TEMPFILE$3 of=/dev/null bs=4K count=$count &> /dev/null
+     time dd if=$TEMPFILE$3 of=/dev/null bs=4096 count=$count &> /dev/null
    done
    ;;
  #

@@ -181,12 +181,12 @@
  #
  _write)
    if [ "$2" = "" ]; then
-     count=100K
+     count=100000
    else
      count=$2
    fi
    while (( 1 )); do
-     time dd if=/dev/zero of=$TEMPFILE$3 bs=4K count=$count
+     time dd if=/dev/zero of=$TEMPFILE$3 bs=4096 count=$count
    done
    ;;
  #

About your script changes, I like to make it portable, and I use the following versions:

GNU bash, version 2.05b.0(1)-release (i386-redhat-linux-gnu)

dd (coreutils) 4.5.3

What shell and coreutils are you using?

Avoiding short counts is easy but avoiding C-style expressions is primitive

- count=100K
+ count=100000

- while (( i-- )); do
+ while (( i=expr $i - 1 )); do

In your opinion are your changes more portable across a wide range of systems?

It has a hard time to read anything else, the slower the disk, the worse.

Suppose rmap undoes the fixes introduced in -rc6.

Have you tried -rc6 plain?

Regards
Michael

It shouldn't, unless bitkeeper made a serious merge error (unlikely). The rmap patch should just change VM code, not the IO improvements.

Having said that, I'd like to thank Michael Frank for his script that reproduces problems. Now the problem is reproducable I can try to fix it ...