06-01-2011 01:56 PM
I discovered that my mbp 2011 has sata 6 problems with ssd..
I found a video file which 80-90% triggers beachballing. I tryed a lot of different 'solutions' as repair disks, turn off motion sensors etc, but nothing works for me. Than I tryed 10.6.8 beta 3 . still beachballing...
so my solution:
1) open console
2) make a big file (2 x your_mem_size)
dd if=/dev/zero of=testio
and wait until it fills up) I made 16g file for my 8g mbp
MacBook:~ e$ ls -lah testio
-rw-r--r-- 1 e staff 16G 1 июн 23:34 testio
3) run this command
while [ 1 -lt 2 ]; do dd if=testio of=/dev/null ; done
while this process is up and running I had not any beachballs but had 100% cpu load and a lot of power consumption.
how it works: the problem is in LPM(power management) so we made IO load and ssd doesnt go to any 'sleep ' state.
06-01-2011 03:45 PM
Neat. Presumably a developer could easily and quickly write a program to frequently utilise the I/O, but to some lesser extent to reduce the CPU load? You can't surely need a constant read to prevent LPM do you? I don't have a Mac so I can't help.
06-06-2011 05:34 AM
After reading SATA docs and 'hdapm' utility source code, I discovered that APM Level SATA command wakes up disk from "ALPM sleep". So I modified the source code to flood ssd with set APL level commands to prevent ALPM Slumber state (which disk enters after 10ms idle), but disk still can enter the Partial state(10microseconds) to save your battery power.
so the link to modified hdapm utility. source and binary included.
##To run hdapm root access required
I copied hdapm to /usr/bin and created the file /etc/rc.local
/usr/bin/hdapm disk0 max > /dev/null &
now hdapm utility runs every time I boot Os x in background.
It eats about 5% of cpu usage.
06-06-2011 07:14 AM - last edited on 06-06-2011 08:57 AM by Crucial_maulmod
Nice hack idea! But when LPM only happens after 10 minutes Idle time, why flood the SSD and cause CPU load instead of just issuing the command every 9 minutes?
Still leaves the question why SSD vendors cannot implement proper LPM handling (obviously it works with the Apple branded* drives)?
*Removed competitor name as per guidelines*
06-06-2011 09:18 AM
Does the video happen to be on Youtube or something? I am still looking for a way to reproduce beachballing my my 2011 MBP. Had it two times now, but that's a bit thin for sophisticated testing.