Performace - CPU usage - WDS bridge - Nanostation5

Installing and Using OpenWrt
1

I wanted to make a bridge (WDS) on this device. I compiled the latest lede (remove all not needed things):

Linux version 4.9.58 (kofec@E5420Mint) (gcc version 7.2.0 (LEDE GCC 7.2.0 r5218-f90f94d) ) #0 Wed Nov 1 21:08:14 2017

I expected to achive about 4 MB/s but I have 2MB/s. Wifi settings:
root@LEDEns5wdsAP:~# cat /etc/config/wireless

config wifi-device 'radio0'
        option type 'mac80211'
        option channel '36'
        option hwmode '11a'
        option path 'platform/ar231x-wmac.1'
        option txpower '20'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option encryption 'psk2'
        option network 'lan'
        option key 'password'
        option ssid 'G5WDS'
        option mode 'ap'
        option wds '1'

But I see that the restriction is on the processor side, so it does not use the full bandwidth nor the standard 11a. I thought that if I do nothing with packages it's done by hardware. At 2MB/s I have 98% CPU used by SoftIRQ.
Does anyone has any idea if more can be achived with this equipment? Maybe some settings on the wifi or network side? Any aggregation? I do not know. Maybe some other settings during compile of this image. I currently have:

cat diffconfig
CONFIG_TARGET_ath25=y
CONFIG_TARGET_ath25_Default=y
CONFIG_TARGET_BOARD="ath25"
CONFIG_DEVEL=y
CONFIG_TOOLCHAINOPTS=y
# CONFIG_ATH_USER_REGD is not set
# CONFIG_GCC_USE_VERSION_5 is not set
CONFIG_GCC_USE_VERSION_7=y
CONFIG_GCC_VERSION="7.2.0"
# CONFIG_IPV6 is not set
# CONFIG_KERNEL_IPV6 is not set
# CONFIG_PACKAGE_MAC80211_MESH is not set
CONFIG_PACKAGE_collectd=y
CONFIG_PACKAGE_collectd-mod-cpu=y
CONFIG_PACKAGE_collectd-mod-interface=y
CONFIG_PACKAGE_collectd-mod-iwinfo=y
CONFIG_PACKAGE_collectd-mod-load=y
CONFIG_PACKAGE_collectd-mod-memory=y
CONFIG_PACKAGE_collectd-mod-network=y
# CONFIG_PACKAGE_dnsmasq is not set
# CONFIG_PACKAGE_firewall is not set
# CONFIG_PACKAGE_iptables is not set
# CONFIG_PACKAGE_kmod-ipt-conntrack is not set
# CONFIG_PACKAGE_kmod-ipt-core is not set
# CONFIG_PACKAGE_kmod-ipt-nat is not set
# CONFIG_PACKAGE_kmod-nf-conntrack is not set
# CONFIG_PACKAGE_kmod-nf-ipt is not set
# CONFIG_PACKAGE_kmod-nf-nat is not set
# CONFIG_PACKAGE_kmod-ppp is not set
# CONFIG_PACKAGE_libip6tc is not set
CONFIG_PACKAGE_libltdl=y
# CONFIG_PACKAGE_odhcpd is not set
CONFIG_PACKAGE_opkg=m
# CONFIG_PACKAGE_ppp is not set
CONFIG_PACKAGE_zlib=y
CONFIG_PACKAGE_kmod-lib-crc-ccitt=y

Thanks in advance

2

Does iwinfo show the link at full 54 Mbps?

There probably hasn't been any development on ath5k for several years. You could try the even further obsolete alternative of madwifi.

3

There was commit which switch ath25 to kernel 4.14 so maybe I can use:

All tagets with >= 4.14 Kernel have offloading included.
You only have to set option flow_offloading 1 in firewall default config section