kernel work week of 3-Feb-2010 HEADS UP

[Matthew Dillon]

    Meta-data test, time find on 11 million inodes (designed such that
    the filesystem meta-data blows out main memory):

    time find /build > /dev/null
    df -i /build
    Filesystem 1K-blocks      Used     Avail Capacity  iused
    BUILDX     897966080 236821248 661144832    26% 11383321

    Without swap cache:

    4.843u 59.522s 14:10.33 7.5%    15+65k 0+0io 0pf+0w
    4.417u 56.161s 11:20.23 8.9%    16+66k 0+0io 8pf+0w		(steady state)
    4.565u 56.035s 11:27.37 8.8%    16+66k 2+0io 36pf+0w	(steady state)

    Remount to clear VM page caches, then enable swap cache:

    4.472u 50.983s 11:52.69 7.7%    15+64k 0+0io 0pf+0w
    4.537u 50.566s 7:27.07 12.3%    16+66k 2+0io 8pf+0w
    4.613u 49.218s 6:42.33 13.3%    16+66k 2+0io 2pf+0w
    4.412u 50.181s 6:00.40 15.1%    16+66k 2+0io 2pf+0w
    4.217u 49.751s 5:26.99 16.5%    16+67k 2+0io 16pf+0w
    4.435u 48.651s 4:54.43 18.0%    16+67k 2+0io 14pf+0w
    4.801u 48.382s 4:27.48 19.8%    16+66k 2+0io 14pf+0w
    4.824u 49.083s 4:05.44 21.9%    15+64k 4+0io 12pf+0w
    4.684u 48.422s 3:41.55 23.9%    16+67k 4+0io 14pf+0w
    4.239u 48.682s 3:24.90 25.8%    16+68k 2+0io 16pf+0w
	(reset burst parameters)
    4.911u 48.598s 3:19.98 26.7%    16+66k 0+0io 0pf+0w
    4.655u 48.334s 2:14.90 39.2%    15+65k 2+0io 12pf+0w
	(hard drive activity almost gone)
	(SSD activity ~30-50MB/sec, mostly reads)
    4.515u 48.598s 1:49.73 48.3%    15+65k 2+0io 10pf+0w	(steady state)
    4.233u 49.028s 1:49.59 48.5%    16+66k 0+0io 0pf+0w		(steady state)
    4.507u 49.059s 1:50.05 48.6%    16+66k 2+0io 8pf+0w		(steady state)
    4.663u 48.912s 1:49.35 48.9%    16+66k 2+0io 8pf+0w		(steady state)
	(basically no HD activity, SSD 30-60MB/sec all reads)

	Steady state reached w/ approximately 4.7GB in the swap
	cache.
	    test28:/root# pstat -s
	    Device          1K-blocks     Used    Avail Capacity  Type
	    /dev/da1s1b      16777088  4719420 12057668    28%    Interleaved

    iostat shows SSD is about 55% busy.  The cpu is 50% busy, so the
    lack of meta-data read-ahead is an issue (maybe something I can
    work on for HAMMER).

						-Matt