Re: [RESEND PATCH v3] crypto: add zBeWalgo compression for zram

[Benjamin Warnke]

Hello,

On(07/03/2018 03:12),Sergey Senozhatsky wrote:
> 
> 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.

I'll split my patch into 2 parts

1st: add zBeWalgo compression algorithm
2nd: enable zBeWalgo to be used by ZRAM

> 
>>   - '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.

as Eric Biggers suggested, I'll add Zstandard to the set of algorithms which compared. What else should I add to the benchmarks?

Benjamin