[CentOS] 2.6 memory management question

Tue Apr 10 23:48:05 UTC 2007
John Summerfield <debian at herakles.homelinux.org>

tblader wrote:
> 
> 
> John Summerfield wrote:
>> tblader wrote:
>>> Hello all.
>>> I have a centos 4.4 box (2.6.9-42.0.10.ELsmp) with 7gig of ram that
>>> doesn't seem to be using swap (also 7gig now).  I say "seem" because
>>> I've noticed ram utilization run around 95% (with oracle and friends
>>> running) and then firing up a couple apps to use that last 5% will
>>> stop the machine dead in it's tracks.
>>>
>>
>> What architecture is this beast?
>>
>>
> 
> Hope this is is of use.
> 
> 
> [2]$ uname -virmop
> 2.6.9-42.0.10.ELsmp #1 SMP Tue Feb 27 09:40:21 EST 2007 x86_64 x86_64 
> x86_64 GNU/Linux
> 
> 
> [2]$ cat /proc/cpuinfo
> processor       : 0
> vendor_id       : AuthenticAMD
> cpu family      : 15
> model           : 67
> model name      : AMD Athlon(tm) 64 FX-62 Dual Core Processor
> stepping        : 2
> cpu MHz         : 2800.038
> cache size      : 1024 KB
> physical id     : 0
> siblings        : 2
> core id         : 0
> cpu cores       : 2
> fpu             : yes
> fpu_exception   : yes
> cpuid level     : 1
> wp              : yes
> flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge 
> mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext lm 
> 3dnowext 3dnow pni cx16
> bogomips        : 5603.52
> TLB size        : 1088 4K pages
> clflush size    : 64
> cache_alignment : 64
> address sizes   : 40 bits physical, 48 bits virtual
> power management: ts fid vid ttp [4] [5]
> 
> processor       : 1
> vendor_id       : AuthenticAMD
> cpu family      : 15
> model           : 67
> model name      : AMD Athlon(tm) 64 FX-62 Dual Core Processor
> stepping        : 2
> cpu MHz         : 2800.038
> cache size      : 1024 KB
> physical id     : 0
> siblings        : 2
> core id         : 1
> cpu cores       : 2
> fpu             : yes
> fpu_exception   : yes
> cpuid level     : 1
> wp              : yes
> flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge 
> mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext lm 
> 3dnowext 3dnow pni cx16
> bogomips        : 5599.20
> TLB size        : 1088 4K pages
> clflush size    : 64
> cache_alignment : 64
> address sizes   : 40 bits physical, 48 bits virtual
> power management: ts fid vid ttp [4] [5]
> 
> 
> 
> [2]$ cat /proc/meminfo
> MemTotal:      7128956 kB
> MemFree:       2132556 kB
> Buffers:        556832 kB
> Cached:        2821408 kB

A supplementary question, can anyone explain what "buffers" and "cached" 
are? I have a performance problem with postgresql (discussion is on the 
postgresql list), and I see those figures displayed by commands such as 
free, top and procinfo but the man pages don't define them.



-- 

Cheers
John

-- spambait
1aaaaaaa at coco.merseine.nu  Z1aaaaaaa at coco.merseine.nu

Please do not reply off-list