Hello,
On (03/06/18 20:59), Benjamin Warnke wrote:
> Currently ZRAM uses compression-algorithms from the crypto-api. ZRAM
> compresses each page individually. As a result the compression algorithm
> is
> forced to use a very small sliding window. None of the available
> compression
> algorithms is designed to achieve high compression ratios with small
> inputs.
I think you first need to merge zBeWalgo (looks like a long way to go)
And then add ZRAM support, as a separate patch.
> - 'ecoham' (100 MiB) This dataset is one of the input files for the
> scientific
> application ECOHAM which runs an ocean simulation. This dataset contains a
> lot of zeros. Where the data is not zero there are arrays of floating
> point
> values, adjacent float values are likely to be similar to each other,
> allowing for high compression ratios.
>
> algorithm | ratio | compression | decompression
> zbewalgo | 12.94 | 294.10 MBit/s | 1242.59 MBit/s
> deflate | 12.54 | 75.51 MBit/s | 736.39 MBit/s
> 842 | 12.26 | 182.59 MBit/s | 683.61 MBit/s
> lz4hc | 12.00 | 51.23 MBit/s | 1524.73 MBit/s
> lz4 | 10.68 | 1334.37 MBit/s | 1603.54 MBit/s
> lzo | 9.79 | 1333.76 MBit/s | 1534.63 MBit/s
>
> - 'source-code' (800 MiB) This dataset is a tarball of the source-code
> from a
> linux-kernel.
>
> algorithm | ratio | compression | decompression
> deflate | 3.27 | 42.48 MBit/s | 250.36 MBit/s
> lz4hc | 2.40 | 104.14 MBit/s | 1150.53 MBit/s
> lzo | 2.27 | 444.77 MBit/s | 886.97 MBit/s
> lz4 | 2.18 | 453.08 MBit/s | 1101.45 MBit/s
> 842 | 1.65 | 64.10 MBit/s | 158.40 MBit/s
> zbewalgo | 1.19 | 52.89 MBit/s | 197.58 MBit/s
>
> - 'hpcg' (8 GiB) This dataset is a (partial) memory-snapshot of the
> running hpcg-benchmark. At the time of the snapshot, that application
> performed a sparse matrix - vector multiplication.
>
> algorithm | ratio | compression | decompression
> zbewalgo | 16.16 | 179.97 MBit/s | 468.36 MBit/s
> deflate | 9.52 | 65.11 MBit/s | 632.69 MBit/s
> lz4hc | 4.96 | 193.33 MBit/s | 1607.12 MBit/s
> 842 | 4.20 | 150.99 MBit/s | 316.22 MBit/s
> lzo | 4.14 | 922.74 MBit/s | 865.32 MBit/s
> lz4 | 3.79 | 908.39 MBit/s | 1375.33 MBit/s
>
> - 'partdiff' (8 GiB) Array of double values. Adjacent doubles are similar,
> but
> not equal. This array is produced by a partial differential equation
> solver
> using a Jakobi-implementation.
>
> algorithm | ratio | compression | decompression
> zbewalgo | 1.30 | 203.30 MBit/s | 530.87 MBit/s
> deflate | 1.02 | 37.06 MBit/s | 1131.88 MBit/s
> lzo | 1.00 | 1741.46 MBit/s | 2012.78 MBit/s
> lz4 | 1.00 | 1458.08 MBit/s | 2013.88 MBit/s
> lz4hc | 1.00 | 173.19 MBit/s | 2012.37 MBit/s
> 842 | 1.00 | 64.10 MBit/s | 2013.64 MBit/s
Hm, mixed feelings.
-ss
