USB3 SSD read speed a bit slow

#1

I am getting only around 350 MB/s read speed from ext USB3 SSD. on desktop this disk achieves 420+ MB/s.
not a big deal for me but I was wondering if hardware wise the rock5 is limited here. My Raspberry Pi 4 gets 221 MB/S via USB3

/: Bus 06.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/1p, 5000M
|__ Port 1: Dev 2, If 0, Class=Mass Storage, Driver=uas, 5000M

rock@rock-5b:~$ sudo hdparm -Tt /dev/sda
/dev/sda:
Timing cached reads: 7186 MB in 2.00 seconds = 3594.97 MB/sec
Timing buffered disk reads: 1098 MB in 3.00 seconds = 365.87 MB/sec
rock@rock-5b:~$ sudo hdparm -Tt /dev/sda
/dev/sda:
Timing cached reads: 7084 MB in 2.00 seconds = 3544.30 MB/sec
Timing buffered disk reads: 1046 MB in 3.01 seconds = 348.06 MB/sec

#2

Prob you can test out if things with cores and irq’s are optimised.

Generally being lazy I just sudo apt-get install irqbalance but did notice it all seems to happen mostly on core zero unless you do.

Then check if its the cores and perf governor that could be limiting perf
sudo taskset -c 4-7 hdparm -t /dev/sda1

Then try a race to idle than the ondemand via
echo performance | sudo tee /sys/bus/cpu/devices/cpu[046]/cpufreq/scaling_governor /sys/class/devfreq/dmc/governor

sudo taskset -c 4-7 hdparm -t /dev/sda

#3

yes this gives better results.
sudo taskset -c 4-7 hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 1246 MB in 3.00 seconds = 415.16 MB/sec

#4

-c 4-7 is your big cores but prob setting echo performance | sudo tee /sys/devices/system/cpu/cpufreq/policy[046]/scaling_governor also has similar effect for all subsequent.

Still haven’t got my head round the big.Little governors / scheduling