Re: Παράξενες καθυστερήσεις όταν γράφω στο δίσκο

[Nick Demou]

τα παρακάτω σέ ένα ταπεινό PC (λεπτομέρειες παρακάτω)

> mkdir /tmp/lolo
> for i in {1..22000}; do dd if=/dev/zero of=/tmp/lolo/pipi$i bs=19000 count=1; done
> time cp /tmp/lolo/* .

real	0m20.081s
user	0m0.512s
sys	0m4.048s
 ndemou @ bedroom ~/temp
> time sync

real	0m0.339s
user	0m0.000s
sys	0m0.020s
> rm pipi*
> rm -rf /tmp/lolo

> uname -a
Linux bedroom 3.0.0-16-generic #28-Ubuntu SMP Fri Jan 27 17:50:54 UTC
2012 i686 i686 i386 GNU/Linux
 ndemou @ bedroom ~
> cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=11.10
DISTRIB_CODENAME=oneiric
DISTRIB_DESCRIPTION="Ubuntu 11.10"
 ndemou @ bedroom ~
> cat /proc/cpuinfo | grep Intel
vendor_id	: GenuineIntel
model name	: Intel(R) Core(TM)2 CPU          6300  @ 1.86GHz
vendor_id	: GenuineIntel
model name	: Intel(R) Core(TM)2 CPU          6300  @ 1.86GHz
> sudo hdparm -I /dev/sda
[sudo] password for ndemou:

/dev/sda:

ATA device, with non-removable media
	Model Number:       WDC WD3200AAKS-00B3A0
	Serial Number:      WD-WCAT14428669
	Firmware Revision:  01.03A01
	Transport:          Serial, SATA 1.0a, SATA II Extensions, SATA Rev 2.5
Standards:
	Supported: 8 7 6 5
	Likely used: 8
Configuration:
	Logical		max	current
	cylinders	16383	16383
	heads		16	16
	sectors/track	63	63
	--
	CHS current addressable sectors:   16514064
	LBA    user addressable sectors:  268435455
	LBA48  user addressable sectors:  625140335
	Logical/Physical Sector size:           512 bytes
	device size with M = 1024*1024:      305244 MBytes
	device size with M = 1000*1000:      320071 MBytes (320 GB)
	cache/buffer size  = 16384 KBytes
Capabilities:
	LBA, IORDY(can be disabled)
	Queue depth: 32
	Standby timer values: spec'd by Standard, with device specific minimum
	R/W multiple sector transfer: Max = 16	Current = 16
	Recommended acoustic management value: 128, current value: 254
	DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6
	     Cycle time: min=120ns recommended=120ns
	PIO: pio0 pio1 pio2 pio3 pio4
	     Cycle time: no flow control=120ns  IORDY flow control=120ns
Commands/features:
	Enabled	Supported:
	    	SMART feature set
	    	Security Mode feature set
	   *	Power Management feature set
	   *	Write cache
	   *	Look-ahead
	   *	Host Protected Area feature set
	   *	WRITE_BUFFER command
	   *	READ_BUFFER command
	   *	NOP cmd
	   *	DOWNLOAD_MICROCODE
	    	Power-Up In Standby feature set
	   *	SET_FEATURES required to spinup after power up
	    	SET_MAX security extension
	    	Automatic Acoustic Management feature set
	   *	48-bit Address feature set
	   *	Device Configuration Overlay feature set
	   *	Mandatory FLUSH_CACHE
	   *	FLUSH_CACHE_EXT
	   *	SMART error logging
	   *	SMART self-test
	   *	General Purpose Logging feature set
	   *	64-bit World wide name
	   *	Segmented DOWNLOAD_MICROCODE
	   *	Gen1 signaling speed (1.5Gb/s)
	   *	Gen2 signaling speed (3.0Gb/s)
	   *	Native Command Queueing (NCQ)
	   *	Host-initiated interface power management
	   *	Phy event counters
	    	DMA Setup Auto-Activate optimization
	   *	Software settings preservation
	   *	SMART Command Transport (SCT) feature set
	   *	SCT Long Sector Access (AC1)
	   *	SCT LBA Segment Access (AC2)
	   *	SCT Error Recovery Control (AC3)
	   *	SCT Features Control (AC4)
	   *	SCT Data Tables (AC5)
	    	unknown 206[12] (vendor specific)
	    	unknown 206[13] (vendor specific)
Security:
	Master password revision code = 65534
		supported
	not	enabled
	not	locked
	not	frozen
	not	expired: security count
		supported: enhanced erase
	56min for SECURITY ERASE UNIT. 56min for ENHANCED SECURITY ERASE UNIT.
Logical Unit WWN Device Identifier: 50014ee1abf6a171
	NAA		: 5
	IEEE OUI	: 0014ee
	Unique ID	: 1abf6a171
Checksum: correct