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View Full Version : [SOLVED] A little tuning for occasional skip playing back recordings 0.24



keepitsimpleengr
October 28th, 2011, 01:25 AM
I recently have been occasionally getting little skips/pauses when playing back recordings.

I fixed this (apparently) by setting the PCI latency for SATA and IDE to 176 from the default 32 (set by the motherboards BIOS). Supposedly this allows fewer I/O disruptions to the large blocksize xfs filesystem.

This link describes the what and how·to better than I can…

http://www.mythtv.org/wiki/PCI_Latency

Earlier I had introduced "de·fragmentation/reorganization" for my xfs disks by running a script using xfs_fsr at 2 a.m. everyday with cron. This helped a prior similar skipping. Here's what it does from it's little log file:
⋯@⋯:/var/log# cat xfs_fsr.log
⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯xfs report
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda3 xfs 144G 135G 9.2G 94% /iso
/dev/sdb1 xfs 1.9T 1.5T 414G 78% /pvr
/dev/sdc1 xfs 1.9T 1.4T 512G 73% /pvs
total - 3.8T 2.9T 935G 76%
⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯frag_report
⋯⋯xfs frag report for /iso (/dev/sda3) ⋯ Wed Oct 26 02:00:02 PDT 2011
actual 6324, ideal 6262, fragmentation factor 0.98%
⋯⋯xfs frag report for /pvr (/dev/sdb1) ⋯ Wed Oct 26 02:00:03 PDT 2011
actual 1147, ideal 1097, fragmentation factor 4.36%
⋯⋯xfs frag report for /pvs (/dev/sdc1) ⋯ Wed Oct 26 02:00:03 PDT 2011
actual 1360, ideal 1087, fragmentation factor 20.07%
⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯reorganizat ion
⋯⋯Wed Oct 26 02:00:04 PDT 2011⋯⋯start⋯⋯xfs_fsr
⋯⋯Exit status for xfs_fsr= 0
⋯⋯Wed Oct 26 04:19:21 PDT 2011⋯⋯-end-⋯-xfs_fsr
⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯frag_report
⋯⋯xfs frag report for /iso (/dev/sda3) ⋯ Wed Oct 26 04:19:21 PDT 2011
actual 6324, ideal 6262, fragmentation factor 0.98%
⋯⋯xfs frag report for /pvr (/dev/sdb1) ⋯ Wed Oct 26 04:19:22 PDT 2011
actual 1147, ideal 1097, fragmentation factor 4.36%
⋯⋯xfs frag report for /pvs (/dev/sdc1) ⋯ Wed Oct 26 04:19:22 PDT 2011
actual 1119, ideal 1090, fragmentation factor 2.59%
⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯endBefore I started doing this, defragmentation was >80%. Since I have added a second 2TB drive. In this busy new season with MLB playoffs, &c, it been running about two hours a night.

This summer it was running about 20 minutes a night. The increase also my be due to the disk getting fuller, up to 76% from about 50%. I should look into the autoexpire/delete/limit, now maxed out at 200GB.

My system combo client/server, AMD 3 CPU 3.1MHz, 2250 Hauppage 2xtuner card, 240 nvidia, 4GB memory, 2x2TB satas and a 320GB sata for system and a little extra recording storage. I comm-flag immediately after starting a recording.