poor fdc(4) performance
Pyun YongHyeon
pyunyh at gmail.com
Sat Nov 12 07:45:27 GMT 2005
On Sat, Nov 12, 2005 at 06:37:11PM +1100, Peter Jeremy wrote:
> On Sat, 2005-Nov-12 16:18:15 +0900, Pyun YongHyeon wrote:
> >I encountered a P3 SMP system that shows poor fdc(4) performance.
> >But when I use larger block size, say 36b, it seems it works
> >as expected.
>
> 36b is one track. My suspicion is that the system isn't fast enough
> to read sequential blocks, one at a time, so you're forced to wait
> a complete revolution (plus a bit) for each block you read.
>
Yes, it could be. But I think the machine is fast enough to read
sequential blocks.
Part of dmesg shows:
CPU: Intel Pentium III (800.03-MHz 686-class CPU)
Origin = "GenuineIntel" Id = 0x686 Stepping = 6
Features=0x387fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,P
AT,PSE36,PN,MMX,FXSR,SSE>
real memory = 402587648 (383 MB)
avail memory = 384385024 (366 MB)
FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
cpu0 (BSP): APIC ID: 0
cpu1 (AP): APIC ID: 1
And I think I got much better result on slow i386 machines except this one.
--
Regards,
Pyun YongHyeon
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