Gentoo Archives: gentoo-user

From: Alex Schuster <wonko@×××××××××.org>
To: gentoo-user@l.g.o
Subject: [gentoo-user] I want to play movies without hangs
Date: Thu, 16 Feb 2012 15:31:02
1 Hi there!
3 Strange things are going on here.
5 I've written here in the past about my performance problems. My dual-core
6 had trouble playing movies without stuttering when there was I/O. It was
7 mainly swapping that caused this, and 8 G were not enough for me running
8 KDE4.
10 Then my hardware broke, and I got new one, except for the system hard
11 drive and the PSU. It's an AMD FX-4100 quad-core with 3.6 GHz, 16 G of
12 RAM. Running gentoo-sources-3.2.1 as kernel. But it seems playing movies
13 got even worse!
15 The videos do not need to have high quality. When I do this, I get
16 interruptions, sometimes for more than a whole second:
18 # dd if=/dev/zero of=/tmp/argh bs=10M count=1000
20 My whole system is encrypted, but the same happens with unencrypted
21 partitions. All are on LVM. When I write to another drive, there is no
22 effect. Throughput is around 50-60 MB/s.
24 Any ideas where to look? I think I'll create a completely fresh
25 kernel .config with genkernel, maybe my own .config has some weird
26 problem. But I tried similar things in the past already, getting a kernel
27 from a live cd, to no effect.
29 I put cache = 10240 into .mplayer/config to get 10 MB of video cached,
30 but I see no effect.
32 Playing music with Amarok is no problem.
34 My SATA drives are in AHCI mode, here's some dmesg info about that:
36 ahci 0000:00:11.0: version 3.0
37 ahci 0000:00:11.0: PCI INT A -> GSI 22 (level, low) -> IRQ 22
38 ahci 0000:00:11.0: AHCI 0001.0100 32 slots 4 ports 3 Gbps 0xf impl SATA
39 mode
40 ahci 0000:00:11.0: flags: 64bit ncq sntf ilck led clo pmp pio slum part
41 ccc sxs
42 scsi0 : ahci
43 scsi1 : ahci
44 scsi2 : ahci
45 scsi3 : ahci
46 ata1: SATA max UDMA/133 abar m1024@0xff70b000 port 0xff70b100 irq 22
47 ata2: SATA max UDMA/133 abar m1024@0xff70b000 port 0xff70b180 irq 22
48 ata3: SATA max UDMA/133 abar m1024@0xff70b000 port 0xff70b200 irq 22
49 ata4: SATA max UDMA/133 abar m1024@0xff70b000 port 0xff70b280 irq 22
50 ahci 0000:02:00.0: PCI INT A -> GSI 19 (level, low) -> IRQ 19
51 ahci 0000:02:00.0: irq 43 for MSI/MSI-X
52 ahci: SSS flag set, parallel bus scan disabled
53 ahci 0000:02:00.0: AHCI 0001.0200 32 slots 2 ports 6 Gbps 0x3 impl SATA
54 mode
55 ahci 0000:02:00.0: flags: 64bit ncq sntf stag led clo pmp pio slum part
56 ccc sxs
57 ahci 0000:02:00.0: setting latency timer to 64
58 scsi4 : ahci
59 scsi5 : ahci
60 ata5: SATA max UDMA/133 abar m512@0xff600000 port 0xff600100 irq 43
61 ata6: SATA max UDMA/133 abar m512@0xff600000 port 0xff600180 irq 43
62 pata_atiixp 0000:00:14.1: PCI INT A -> GSI 16 (level, low) -> IRQ 16
63 scsi6 : pata_atiixp
64 scsi7 : pata_atiixp
65 ata7: PATA max UDMA/100 cmd 0x1f0 ctl 0x3f6 bmdma 0xf000 irq 14
66 ata8: PATA max UDMA/100 cmd 0x170 ctl 0x376 bmdma 0xf008 irq 15
68 (ata7/8 is the additional PATA controller, seen with the pata_atiixp
69 driver. I have one drive there, but it is not being used.)
71 When my new girl-friend comes over and we want to watch a movie, and it
72 stutters... she will ask why I don't simply use Windows to get
73 better performance, her five year old PC would do this just fine. Wat do
74 I tell her? WHAT DO I TELL HER??
77 And then there's what happened yesterday. A world update was going on,
78 with libreoffice, firefox, wine and thunderbird emerging in parallel, all
79 big packages. I have the PORTAGE_TMPDIR on a 5GB tmpfs, only libreoffice
80 is being compiled on disk. Suddenly, my system became very unresponsive,
81 the mouse had disappeared, the KDE widgets did not update, and xosview
82 showed a load of 23. All 4 cores were at 100%, the type of usage was
83 io-wait. How can I find out in such a case which processes are waiting
84 for I/O? top showed nothing. The Ctrl-Esc task viewer of KDE showed some
85 processes being 'inactive on hard drive', does this men those are the
86 waiting tasks? They varied, they were mostly Akonadi stuff. I stopped
87 akonadi, and after a while the load dropped. But this may be a
88 coincidence.
90 After all had calmed down, I had 2G of swap in use. 16G total RAM, all
91 being used of course, but only 8G being needed according to the -/+
92 buffers/cache line in free -m, the other 8G are cache. Does my Linux
93 somehow prefer to have this much cache, even if tmpfs stuff gets put into
94 swap? I have vm.swappiness = 0 in /etc/sysctl.conf.
96 Is there a command to show me what processes the memory in swap belongs
97 to?
99 Wonko


Subject Author
Re: [gentoo-user] I want to play movies without hangs Mark Knecht <markknecht@×××××.com>
Re: [gentoo-user] I want to play movies without hangs Paul Hartman <paul.hartman+gentoo@×××××.com>
Re: [gentoo-user] I want to play movies without hangs Walter Dnes <waltdnes@××××××××.org>