hdparm -T 与系统缓存性能

hdparm -T这个命令其实是测试系统缓存（cache）性能的。并不读取硬盘。我发现我的电脑在xwindows下的测试成绩只有在控制台下的一半儿，难道xwindows会降低
系统缓存的性能？大家是否也有同样的问题，谁能给解释一下？

机器是老ibm笔记本：tualatin 1.13G,256M SDRAM，Momentus 40G 8M buffer harddisk.
kernel 2.6.16.19 xorg7 fvwm

请给点数据让大家看看

好，我先睡了，明天起床贴上来。

我的î不多阿

我一般用hdparm -Tt来测，缓存和实际读写都测了。另外在xwindow下测可能因为xwindow的内存用的多，在物理内存不变的情况下用来作磁盘缓存的物理内存就少了，速度也慢了。

hdparm -i /dev/hda

/dev/hda:

Model=ST94811A, FwRev=3.04, SerialNo=3KW1M3D0
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs RotSpdTol>.5% }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
BuffType=unknown, BuffSize=8192kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=78140160
IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
AdvancedPM=yes: unknown setting WriteCache=enabled
Drive conforms to: ATA/ATAPI-6 T13 1410D revision 2: ATA/ATAPI-1 ATA/ATAPI-2 ATA/ATAPI-3 ATA/ATAPI-4 ATA/ATAPI-5 ATA/ATAPI-6

* signifies the current active mod



hdparm -v /dev/hda

/dev/hda:
multcount = 16 (on)
IO_support = 3 (32-bit w/sync)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 256 (on)
geometry = 16383/255/63, sectors = 78140160, start = 0

控制台下的成绩:
hdparm -T /dev/hda

/dev/hda:
Timing cached reads: 812 MB in 2.00 seconds = 405.45 MB/sec
进入xwindows后的成绩:
hdparm -T /dev/hda

/dev/hda:
Timing cached reads: 536 MB in 2.00 seconds = 267.64 MB/sec

下面是硬盘的实际读写测试,在控制台下和xwindows下差不多:
hdparm -t /dev/hda

/dev/hda:
Timing buffered disk reads: 92 MB in 3.00 seconds = 30.62 MB/sec

haha@rainFlower:~$ sudo hdparm -tT /dev/sda
Password:

/dev/sda:
Timing cached reads: 3928 MB in 2.00 seconds = 1964.72 MB/sec
Timing buffered disk reads: 96 MB in 3.06 seconds = 31.39 MB/sec

因为我的内存是SDRAM 133,所以很慢.
但不知为什么在控制台下与在xwindows下的性能不一样.
也许是5楼说的原因.