Re: EXT4-ish "fixes" in UBIFS

From: Trenton D. Adams
Date: Thu Apr 02 2009 - 20:59:37 EST


On Thu, Apr 2, 2009 at 6:54 PM, Trenton D. Adams
<trenton.d.adams@xxxxxxxxx> wrote:
> On Thu, Apr 2, 2009 at 6:38 PM, Christian Kujau <lists@xxxxxxxxxxxxxxx> wrote:
>> On Thu, 2 Apr 2009, Trenton D. Adams wrote:
>>> I'm thinking of writing a script that monitors performance, and
>>> remounts as needed, lol.  WHAT A HACK. hehe.
>>
>> Ugh....my brain hurts :-\
>>
>> Christian.
>
> Yeah, mine too.
>

Just to make it hurt more for you, here you go...

On one console I run...
dd if=/dev/zero of=/tmp/bigfile bs=1M count=2000

On another I run...
perf-mon.sh
remounting with sync option, performance dropping
remounting without sync option, performance has stabilized

It may be better to write a C program that does a 1M fsync, and if
it's taking too long, then remount, lol. Also, this script here,
using 1 min load average, will catch CPU intensity as well, which is
not really what I want. Ah, it is a hack indeed. ROFL

#!/bin/sh

while true; do
UPTIME=$(uptime | xargs | cut -d ' ' -f10 | sed 's/,//');
if [ "$(echo "$UPTIME > 1" | bc)" -eq "1" ]; then
mount | egrep 's-sys.*sync' >/dev/null
if [ "$?" -ne "0" ]; then
echo "remounting with sync option, performance dropping";
mount -o remount,rw,sync /dev/s/sys /;
fi
else
mount | egrep 's-sys.*sync' > /dev/null
if [ "$?" -eq "0" ]; then
echo "remounting without sync option, performance has stabilized";
mount -o remount,rw /dev/s/sys /;
fi
fi;
sleep 1
done
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