Problem in EROFS: Not able to read the files after mount

[Saumya Panda]

Hi Gao,
  I am trying to evaluate Erofs on my device. Right now SquashFS is used
for system files. Hence I am trying to compare Erofs with SquashFs. On my
device with the below environment I am seeing Erofs is 3 times faster than
SquashFS 128k (I used enwik8 (100MB) as testing file)) while doing Seq
Read. Your test result shows it is near to SquasFs 128k. How Erofs is so
fast for Seq Read?  I also tested  it on Suse VM with low memory(free
memory 425MB) and I am seeing Erofs is pretty fast.

Also Can you tell me how to run FIO on directory instead of files ?
 fio -filename=$i -rw=read -bs=4k -name=seqbench

             Test on Embedded Device:

Total Memory 5.5 GB:

 Free Memory 1515

 No Swap


$: /fio/erofs_test]$ free -m

              total        used        free      shared  buff/cache
available

Mem:           5384        2315        1515        1378        1553
1592

Swap:             0           0           0





Seq Read



Rand Read





squashFS 4k



51.8MB/s

1931msec

45.7MB/s

2187msec



SquashFS 128k



116MB/s

861msec

14MB/s

877msec



SquashFS 1M



124MB/s-124MB/s

805msec

119MB/s

837msec





Erofs 4k



658MB/s-658MB/s

152msec



103MB

974msec







 Test on Suse VM:


Total Memory 1.5 GB:

 Free Memory 425

 No Swap

localhost:/home/saumya/Documents/erofs_test # free -m
              total        used        free      shared  buff/cache
available
Mem:           1436         817         425           5         192
444
Swap:             0           0           0






Seq Read



Rand Read





squashFS 4k



30.7MB/s

3216msec

9333kB/s

10715msec



SquashFS 128k



318MB/s

314msec

5946kB/s

16819msec











Erofs 4k



469MB/s

213msec



11.9MB/s

8414msec











On Wed, Jan 29, 2020 at 10:30 AM Gao Xiang <hsiangkao at aol.com> wrote:

> On Wed, Jan 29, 2020 at 09:43:37AM +0530, Saumya Panda wrote:
> >
> > localhost:~> fio --name=randread --ioengine=libaio --iodepth=16
> > --rw=randread --bs=4k --direct=0 --size=512M --numjobs=4 --runtime=240
> > --group_reporting --filename=/mnt/enwik9_erofs/enwik9
> >
> > randread: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T)
> > 4096B-4096B, ioengine=libaio, iodepth=16
>
> And I don't think such configuration is useful to calculate read
> ampfication
> since you read 100% finally, use multi-thread without memory limitation
> (all
> compressed data will be cached, so the total read is compressed size).
>
> I have no idea what you want to get via doing comparsion between EROFS and
> Squashfs. Larger block size much like readahead in bulk. If you benchmark
> uncompressed file systems, you will notice such filesystems cannot get such
> high 100% randread number.
>
> Thank,
> Gao Xiang
>
>

-- 
Thanks,
Saumya Prakash Panda
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