Long night marathon is over. Finally I have latest trunk build without non-sense (for me) USB and PPP modules (on Ubuntu 64bit running under VirtualBox running on 32bit Windows ;-) ), that allowed me to install also luci-app-qos and still I have 184kB free including LUCI (wasn't possible before on my WR841ND V7.1).
Build (http://wiki.openwrt.org/doc/howto/firmware.build#cleanup) with parameter "make image PROFILE=TLWR841NDV7 PACKAGES="-ppp -ppp-mod-pppoe crda kmod-ath kmod-cfg80211 wireless-tools luci" (not sure if crda, kmod-ath, kmod-cfg80211 are really required or are added automatically trough dependences, but I was trying not to brick my router).
resulted in packages "base-files busybox crda dnsmasq dropbear firewall hotplug2 iptables kernel kmod-ath kmod-ath9k kmod-button-hotplug kmod-cfg80211 kmod-input-core kmod-input-gpio-buttons kmod-input-polldev kmod-ipt-nathelper kmod-leds-gpio libc libgcc luci mtd opkg swconfig uci udevtrigger wireless-tools wpad-mini".
While running QOS I'm using in /etc/config/qos following (in some configurations there is "wan" instead of "eth1"), 6MBIT up and down.
config 'interface' 'eth1'
option 'classgroup' 'Default'
option 'enabled' '1'
option 'overhead' '1'
option 'download' '6000'
option 'upload' '6000'
Finally after starting QOS I do not loose connectivity, so it allows me to enable startup script, but was working till reboot - then QOS was not activated fully despite of "ENABLED" startup settings in INITSCRIPTS section of LUCI (or "/etc/init.d/qos enable" as described here - http://wiki.openwrt.org/doc/uci/qos). I modded startup script /etc/init.d/qos in the following way (added qos-start in boot section) and now even after reboot it's fine and enabled by default :
root@OpenWrt:~# cat /etc/init.d/qos
# Copyright (C) 2006 OpenWrt.org
/usr/lib/qos/generate.sh firewall | sh
And finally - while downloading something, HTTP and others connections are running fine (eg. while heavy download ping to some server went to 900ms!!, and now to 80ms from original 4ms)
Could someone with better experience confirm whether this is a bug or not ? Why at boot it's launched " /usr/lib/qos/generate.sh firewall | sh" however "qos-start" starts "/usr/lib/qos/generate.sh all | sh" ???