Problem with virtually no buffer usage in 2.4.21mdk kernel

Problem with virtually no buffer usage in 2.4.21mdk kernel

[Robert Creager]

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[Please CC me personally, as I'm not subscribed]

Hey folks,

I'm using a custom built 2.4.21 kernel from the Mandrake 9.1 distribution.  The hardware is dual AMD Athlon 2600+ system with 2Gb of registered DDR ECC memory, SCSI and ATA disks.

My apparent problem is I'm seeing virtually no buffer usage, as checked from /proc/meminfo.  The system has been up for 11 days, with heavy dB and file access activity (Gb's worth per day), yet the buffer usage never budges.  Am I missing something fundamental, have I boffed the kernel build, or is there a problem?  I would appreciate any pointers.

        total:    used:    free:  shared: buffers:  cached:
Mem:  2119151616 2068426752 50724864        0    90112 1888358400
Swap: 2089177088 70832128 2018344960
MemTotal:      2069484 kB
MemFree:         49536 kB
MemShared:           0 kB
Buffers:            88 kB
Cached:        1823808 kB
SwapCached:      20292 kB
Active:        1209640 kB
Inactive:       712324 kB
HighTotal:     1179136 kB
HighFree:         2044 kB
LowTotal:       890348 kB
LowFree:         47492 kB
SwapTotal:     2040212 kB
SwapFree:      1971040 kB

Thanks for your time,
Rob

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Re: Problem with virtually no buffer usage in 2.4.21mdk kernel

[Bruce Harada]

On Sat, 24 May 2003 22:33:20 -0600
Robert Creager <Robert_Creager@LogicalChaos.org> wrote:

> My apparent problem is I'm seeing virtually no buffer usage, as checked from
> /proc/meminfo.  The system has been up for 11 days, with heavy dB and file
> access activity (Gb's worth per day), yet the buffer usage never budges.  Am
> I missing something fundamental, have I boffed the kernel build, or is there
> a problem?  I would appreciate any pointers.
> 
>         total:    used:    free:  shared: buffers:  cached:
> Mem:  2119151616 2068426752 50724864        0    90112 1888358400
> Swap: 2089177088 70832128 2018344960
> MemTotal:      2069484 kB
> MemFree:         49536 kB
> MemShared:           0 kB
> Buffers:            88 kB
> Cached:        1823808 kB
> SwapCached:      20292 kB
> Active:        1209640 kB
> Inactive:       712324 kB
> HighTotal:     1179136 kB
> HighFree:         2044 kB
> LowTotal:       890348 kB
> LowFree:         47492 kB
> SwapTotal:     2040212 kB
> SwapFree:      1971040 kB

Count the columns - the '0' is for shared memory, not buffers.
As for why shared memory shows as zero, that's in the FAQ:

 http://www.tux.org/lkml/#s14-3

Re: Problem with virtually no buffer usage in 2.4.21mdk kernel

[Robert Creager]

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Hey Bruce,

On Sun, 25 May 2003 15:18:16 +0900
Bruce Harada <bharada@coral.ocn.ne.jp> said something like:

> On Sat, 24 May 2003 22:33:20 -0600
> Robert Creager <Robert_Creager@LogicalChaos.org> wrote:
> 
> > My apparent problem is I'm seeing virtually no buffer usage, as checked from /proc/meminfo
[snip]
> > Buffers:            88 kB
[snip]
> 
> Count the columns - the '0' is for shared memory, not buffers.
> As for why shared memory shows as zero, that's in the FAQ:
> 
>  http://www.tux.org/lkml/#s14-3
> 

That's why I said virtually no buffer usage (not shared memory).  I'm looking at the 88kb (90112).  On my other two systems, both 2.4.19 with 640Mb and 128Mb memory, the buffer usage is 86Mb, and 44Mb respectivly.

Other thoughts?

Thanks,
Rob

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Re: Problem with virtually no buffer usage in 2.4.21mdk kernel

[Bruce Harada]

On Sun, 25 May 2003 08:12:53 -0600
Robert Creager <Robert_Creager@LogicalChaos.org> wrote:

> That's why I said virtually no buffer usage (not shared memory).  I'm
> looking at the 88kb (90112).  On my other two systems, both 2.4.19 with
> 640Mb and 128Mb memory, the buffer usage is 86Mb, and 44Mb respectivly.
> 
> Other thoughts?

Ah, my apologies. As for why your buffer usage is so low, it's likely a bit
difficult to tell whether it's indicative of a problem without knowing what
patches have been applied to the Mandrake kernel. Also, I believe the buffers
value these days isn't as useful a metric as it used to be, so personally I
wouldn't worry about it too much, unless you're seeing problems with the box.

Re: Problem with virtually no buffer usage in 2.4.21mdk kernel

[Robert Creager]

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On Tue, 27 May 2003 02:41:41 +0900
Bruce Harada <bharada@coral.ocn.ne.jp> said something like:

> On Sun, 25 May 2003 08:12:53 -0600
> Robert Creager <Robert_Creager@LogicalChaos.org> wrote:
> 
> > That's why I said virtually no buffer usage (not shared memory).  I'm
> > looking at the 88kb (90112).  On my other two systems, both 2.4.19 with
> > 640Mb and 128Mb memory, the buffer usage is 86Mb, and 44Mb respectivly.
> > 
> > Other thoughts?
> 
> Ah, my apologies. As for why your buffer usage is so low, it's likely a bit
> difficult to tell whether it's indicative of a problem without knowing what
> patches have been applied to the Mandrake kernel. Also, I believe the buffers
> value these days isn't as useful a metric as it used to be, so personally I
> wouldn't worry about it too much, unless you're seeing problems with the box.
> 

I'm not seeing any problems that I'm aware of, just trying to eak out a little more performance out of the box, and the lack of disk buffer usage seems suspicious.

I may try backing of to a known released kernel, and see what happens...

Cheers,
Rob

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