Since we are always trying to squeeze the most out of our boxes, I
thought I would share a few of the performance tuning tricks I have been
experimenting with lately.
1) Disk and FS
If you are using ext3, add the append option
append="rootflags=data=writeback" This will make the journal less I/O
intense, however you will sacrifice some data integrity in case of a
crash.
in /etc/fstab mount your filesystems with "noatime" as an option, this
will stop the system from writing access times about files when you open
them for reading.
NOTE: PLEASE BE CAREFUL WITH THE NEXT OPTION, YOUR DISK MAY NOT SUPPORT
ALL THESE
hdparm -d1 -m16 -a128 -W1 -A1 -X12 /dev/hd?
check hdparms man page for a list of what these all do. You can query
your drive for most of the options it can handle. Also, these may not
be the best they can be, I am still experimenting.
ALSO COULD BE DANGEROUS
elvtune -r 2048 -w 4096 /dev/hd?
This one may be obvious, but I will include it anyways.
Make your /mnt/store (or whatever your are buffering too) on a different
partition or disk from your / and /var, this way your system and your
mysql database aren't trying to access the same drive/partition as your
buffering to.
2) Kernel options
I will only share the bdflush parameters I am using right now, when I am
finished messing with powertweak and find the right options, I will
share those. Until then add this to your /etc/sysctl.conf
vm.bdflush = 100 800 128 512 15 5000 500 1584 2
Again, this might not be the best options, I will let the list know if I
find better ones.
3) Mythtv options
It seems to me that the blueosd is less of a system drain than the
defaultosd is. The reason I say this is when I use the defaultosd I get
video and audio skips when the menu fades, but I don't when I use
blueosd. It might just be this ancient machine though.
With these tweaks I have been able to get an old Athalon 550 to record
and playback at decent quality with no skips, jitters, etc.
Good luck!
Matt Brichacek
thought I would share a few of the performance tuning tricks I have been
experimenting with lately.
1) Disk and FS
If you are using ext3, add the append option
append="rootflags=data=writeback" This will make the journal less I/O
intense, however you will sacrifice some data integrity in case of a
crash.
in /etc/fstab mount your filesystems with "noatime" as an option, this
will stop the system from writing access times about files when you open
them for reading.
NOTE: PLEASE BE CAREFUL WITH THE NEXT OPTION, YOUR DISK MAY NOT SUPPORT
ALL THESE
hdparm -d1 -m16 -a128 -W1 -A1 -X12 /dev/hd?
check hdparms man page for a list of what these all do. You can query
your drive for most of the options it can handle. Also, these may not
be the best they can be, I am still experimenting.
ALSO COULD BE DANGEROUS
elvtune -r 2048 -w 4096 /dev/hd?
This one may be obvious, but I will include it anyways.
Make your /mnt/store (or whatever your are buffering too) on a different
partition or disk from your / and /var, this way your system and your
mysql database aren't trying to access the same drive/partition as your
buffering to.
2) Kernel options
I will only share the bdflush parameters I am using right now, when I am
finished messing with powertweak and find the right options, I will
share those. Until then add this to your /etc/sysctl.conf
vm.bdflush = 100 800 128 512 15 5000 500 1584 2
Again, this might not be the best options, I will let the list know if I
find better ones.
3) Mythtv options
It seems to me that the blueosd is less of a system drain than the
defaultosd is. The reason I say this is when I use the defaultosd I get
video and audio skips when the menu fades, but I don't when I use
blueosd. It might just be this ancient machine though.
With these tweaks I have been able to get an old Athalon 550 to record
and playback at decent quality with no skips, jitters, etc.
Good luck!
Matt Brichacek