| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Fri, 6 Jun 2008 14:07:55 -0700 (PDT)
From: Benjamin Kidwell <benjkidwell@...oo.com>
To: linux-kernel@...r.kernel.org
Cc: benjkidwell@...oo.com
Subject: Linux-next Alsa hda_intel events/0 high CPU usage, bisected
Linux-next Alsa hda_intel events/0 high CPU usage, bisected
During sound playback with recent linux-next-20080806 I observed much higher
than usual cpu usage for the events/0 process, locked at a near constant 4.3%
according to ps. 2.6.25-rc5 does not exhibit this behavior on my machine.
I git-bisected and arrived at this commit to sound/pci/hda/hda_intel.c
8a4bd4dff53ad23c32ffc0b366e592319dd566a4
which fixes IRQ timing issues.
As a very crude debugging test, I short-circuited this decision:
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1489,7 +1489,7 @@
}
if (pos % azx_dev->period_bytes > azx_dev->period_bytes / 2)
- return 0; /* NG - it's below the period boundary */
+ return 1; /* Tell a lie */
return 1; /* OK, it's fine */
}
and sure enough, the events/0 process cpu load dropped down to its usual
level, undetectable with top and ps. I don't know if the high events/0 load is
the intended behavior of this code on my hardware or not. Sound playback and
general system behavior seemed subjectively equivalent regardless of the
highly active events/0 process.
This report is from /dev/random_user and I'm not qualified to diff bugs vs.
features, so sorry if this message is just noise. I'm happy to provide more
info if needed.
Here's a bit of relevant info from my machine from a run with the high
events/0 usage. A few bits of dmesg:
[ 0.066419] ACPI: Core revision 20080321
[ 0.075988] ENABLING IO-APIC IRQs
[ 0.075988] ..TIMER: vector=0x31 apic1=0 pin1=2 apic2=-1 pin2=-1
[ 0.075988] ..MP-BIOS bug: 8254 timer not connected to IO-APIC
[ 0.075988] ...trying to set up timer (IRQ0) through the 8259A ...
failed.
[ 0.075988] ...trying to set up timer as Virtual Wire IRQ... works.
[ 0.086170] CPU0: Intel(R) Pentium(R) 4 CPU 3.00GHz stepping 09
[ 0.086986] CPU 1 irqstacks, hard=c0359000 soft=c0357000
[ 0.086986] Booting processor 1/1 ip 6000
[ 0.096985] Initializing CPU#1
[ 0.096985] Calibrating delay using timer specific routine.. 5998.67
BogoMIPS (lpj=2999338)
[ 0.160975] ACPI: bus type pci registered
[ 0.160975] PCI: MCFG configuration 0: base e0000000 segment 0 buses
0 -
255
[ 0.160975] PCI: MCFG area at e0000000 reserved in E820
[ 0.160975] PCI: Using MMCONFIG for extended config space
[ 0.160975] PCI: Using configuration type 1 for base access
[ 0.160975] Setting up standard PCI resources
[ 0.166580] ACPI: EC: Look up EC in DSDT
[ 0.172973] ACPI: Interpreter enabled
[ 0.172977] ACPI: (supports S0 S3 S5)
[ 0.173185] ACPI: Using IOAPIC for interrupt routing
[ 0.179736] ACPI: PCI Root Bridge [PCI0] (0000:00)
[ 0.180460] PCI: Transparent bridge - 0000:00:14.4
[ 0.180566] ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]
[ 0.180972] ACPI: PCI Interrupt Routing Table [\_SB_.PCI0.P2P_._PRT]
[ 0.194970] ACPI: PCI Interrupt Link [LNKA] (IRQs 3 4 5 6 7 10 11)
*0, disabled.
[ 0.195606] ACPI: PCI Interrupt Link [LNKB] (IRQs 3 4 5 6 7 10 11)
*0, disabled.
[ 0.196309] ACPI: PCI Interrupt Link [LNKC] (IRQs 3 4 5 6 7 10 11)
*0, disabled.
[ 0.197026] ACPI: PCI Interrupt Link [LNKD] (IRQs 3 4 5 6 7 10 11)
*0, disabled.
[ 0.197969] ACPI: PCI Interrupt Link [LNKE] (IRQs 3 4 5 6 *7 10 11)
[ 0.198286] ACPI: PCI Interrupt Link [LNKF] (IRQs 3 4 5 6 7 10 11)
*0, disabled.
[ 0.198989] ACPI: PCI Interrupt Link [LNK0] (IRQs 3 4 5 6 7 10 *11)
[ 0.199567] ACPI: PCI Interrupt Link [LNK1] (IRQs 3 4 *5 6 7 10 11)
[ 17.037709] piix4_smbus 0000:00:14.0: Found 0000:00:14.0 device
[ 17.135812] ACPI: PCI Interrupt 0000:00:14.2[A] -> GSI 16 (level,
low) -> IRQ 16
[ 27.183697] hda-intel: Invalid position buffer, using LPIB read
method instead.
output of lsmod:
ipv6 223300 12
cpufreq_userspace 2988 0
cpufreq_stats 4748 0
cpufreq_powersave 1792 0
cpufreq_ondemand 6796 0
freq_table 3592 2 cpufreq_stats,cpufreq_ondemand
sbs 11144 0
sbshc 4864 1 sbs
container 3456 0
battery 10116 0
iptable_filter 2688 0
ip_tables 9872 1 iptable_filter
x_tables 12164 1 ip_tables
ac 4228 0
loop 13452 0
af_packet 15232 2
snd_hda_intel 55692 3
snd_pcm 62084 1 snd_hda_intel
snd_timer 18312 1 snd_pcm
serio_raw 5124 0
snd 39092 9 snd_hda_intel,snd_pcm,snd_timer
psmouse 23432 0
i2c_piix4 7696 0
soundcore 5984 1 snd
snd_page_alloc 7304 2 snd_hda_intel,snd_pcm
i2c_core 18324 1 i2c_piix4
ati_agp 6540 0
agpgart 26312 1 ati_agp
button 6032 0
evdev 8704 3
ext3 116616 1
jbd 39828 1 ext3
mbcache 6404 1 ext3
usbhid 19364 0
hid 36096 1 usbhid
ide_cd_mod 29444 0
cdrom 33056 1 ide_cd_mod
sd_mod 20760 3
pata_atiixp 4608 0
8139too 20992 0
8139cp 17408 0
mii 4480 2 8139too,8139cp
atiixp 3588 0 [permanent]
ehci_hcd 31372 0
ohci_hcd 20228 0
sata_sil 7560 2
pata_acpi 3968 0
ata_generic 4868 0
usbcore 120176 4 usbhid,ehci_hcd,ohci_hcd
libata 139616 4
pata_atiixp,sata_sil,pata_acpi,ata_generic
scsi_mod 85448 2 sd_mod,libata
dock 7824 1 libata
ide_pci_generic 4100 0 [permanent]
ide_core 84904 3 ide_cd_mod,atiixp,ide_pci_generic
thermal 15004 0
processor 31424 1 thermal
fan 4228 0
fuse 45468 3
audio entry snipped from lspci -vvv
00:14.2 Audio device: ATI Technologies Inc IXP SB4x0 High Definition
Audio Controller (rev 01)
Subsystem: Micro-Star International Co., Ltd. Unknown device 725a
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
ParErr- Stepping- SERR- FastB2B-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=slow >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
Latency: 64, Cache Line Size: 32 bytes
Interrupt: pin ? routed to IRQ 16
Region 0: Memory at fdff4000 (64-bit, non-prefetchable)
[size=16K]
Capabilities: [50] Power Management version 2
Flags: PMEClk- DSI- D1- D2- AuxCurrent=55mA
PME(D0+,D1-,D2-,D3hot+,D3cold+)
Status: D0 PME-Enable- DSel=0 DScale=0 PME-
Capabilities: [60] Message Signalled Interrupts: Mask- 64bit+
Queue=0/0 Enable-
Address: 0000000000000000 Data: 0000
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists