Re: swapping and the value of /proc/sys/vm/swappiness

Marcelo Tosatti
2004-09-09T13:39:25Z

On Wed, Sep 08, 2004 at 10:06:20PM -0500, Ray Bryant wrote:
> Marcelo,
>
> For what it is worth, here are the benchmark results for the kernel with
> the patch I discussed before, along with the previous 2.6.9-rc1-mm3 results:
>
> Kernel Version 2.6.9-rc1-mm3:
> Total I/O Avg Swap min max pg cache min max
> ----------- --------- ------- ------ --------- ------- -------
> 0 274.80 MB/s 10511 MB ( 5644, 14492) 13293 MB ( 8596, 17156)
> 20 267.02 MB/s 12624 MB ( 5578, 16287) 15298 MB ( 8468, 18889)
> 40 267.66 MB/s 13541 MB ( 6619, 17461) 16199 MB ( 9393, 20044)
> 60 233.73 MB/s 18094 MB ( 16550, 19676) 20629 MB ( 19103, 22192)
> 80 213.64 MB/s 20950 MB ( 15844, 22977) 23450 MB ( 18496, 25440)
> 100 164.58 MB/s 26004 MB ( 26004, 26004) 28410 MB ( 28327, 28455)
>
> Kernel Version 2.6.9-rc1-mm3-kdb-nrmap:
> Total I/O Avg Swap min max pg cache min max
> ----------- --------- ------- ------ --------- ------- -------
> 0 286.93 MB/s 7288 MB ( 4847, 14536) 10122 MB ( 7771, 17138)
> 20 252.43 MB/s 13305 MB ( 3950, 18337) 15938 MB ( 6866, 20876)
> 40 268.52 MB/s 11538 MB ( 5333, 17298) 14238 MB ( 8247, 19836)
> 60 242.72 MB/s 16367 MB ( 8652, 21217) 18909 MB ( 11514, 23561)
> 80 212.94 MB/s 19424 MB ( 5632, 24047) 21937 MB ( 8567, 26469)
> 100 161.66 MB/s 26006 MB ( 26004, 26007) 28445 MB ( 28407, 28471)
>
> Except for the swappiness = 20 case, things are a smallish bit better for
> the modified kernel than 2.6.9-rc1-mm3. Clearly we haven't found the root
> of this problem yet.

Indeed.

> Have you still been unable to duplicate this problem on a small i386
> platform?

Yes right, I have been unable to duplicate the problem on small i386 box.
What about your tests?