Re: [mm] e6e88712e4: stress-ng.tmpfs.ops_per_sec -69.7% regression

[Rong Chen <rong.a.chen@intel.com>]

On 10/30/20 10:58 PM, Matthew Wilcox wrote:
> On Fri, Oct 30, 2020 at 10:02:45PM +0800, Chen, Rong A wrote:
>> On 10/30/2020 9:17 PM, Matthew Wilcox wrote:
>>> On Fri, Oct 30, 2020 at 03:17:15PM +0800, kernel test robot wrote:
>>>> Details are as below:
>>>> -------------------------------------------------------------------------------------------------->
>>>>
>>>>
>>>> To reproduce:
>>>>
>>>>           git clone https://github.com/intel/lkp-tests.git
>>>>           cd lkp-tests
>>>>           bin/lkp install job.yaml  # job file is attached in this email
>>>>           bin/lkp run     job.yaml
>>> Do you actually test these instructions before you send them out?
>>>
>>> hdd_partitions: "/dev/disk/by-id/ata-WDC_WD2500BEKT-00PVMT0_WD-WX11A23L4840-part
>>> 1"
>>> ssd_partitions: "/dev/nvme1n1p1 /dev/nvme0n1p1"
>>> rootfs_partition: "/dev/disk/by-id/ata-INTEL_SSDSC2CW240A3_CVCV204303WP240CGN-part1"
>>>
>>> That's _very_ specific to a given machine.  I'm not familiar with
>>> this test, so I don't know what I need to change.
>>
>> Hi Matthew,
>>
>> Sorry about that, I copied the job.yaml file from the server,
>> the right way to do is to set your disk partitions in the yaml,
>> please see https://github.com/intel/lkp-tests#run-your-own-disk-partitions.
>>
>> there is another reproduce script attached in the original mail
>> for your reference.
> Can you reproduce this?  Here's my results:
>
> # stress-ng "--timeout" "100" "--times" "--verify" "--metrics-brief" "--sequential" "96" "--class" "memory" "--minimize" "--exclude" "spawn,exec,swap,stack,atomic,bad-altstack,bsearch,context,full,heapsort,hsearch,judy,lockbus,lsearch,malloc,matrix-3d,matrix,mcontend,membarrier,memcpy,memfd,memrate,memthrash,mergesort,mincore,null,numa,pipe,pipeherd,qsort,radixsort,remap,resources,rmap,shellsort,skiplist,stackmmap,str,stream,tlb-shootdown,tree,tsearch,vm-addr,vm-rw,vm-segv,vm,wcs,zero,zlib"
> stress-ng: info:  [7670] disabled 'oom-pipe' as it may hang or reboot the machine (enable it with the --pathological option)
> stress-ng: info:  [7670] dispatching hogs: 96 tmpfs
> stress-ng: info:  [7670] successful run completed in 100.23s (1 min, 40.23 secs)
> stress-ng: info:  [7670] stressor       bogo ops real time  usr time  sys time   bogo ops/s   bogo ops/s
> stress-ng: info:  [7670]                           (secs)    (secs)    (secs)   (real time) (usr+sys time)
> stress-ng: info:  [7670] tmpfs              8216    100.10    368.02    230.89        82.08        13.72
> stress-ng: info:  [7670] for a 100.23s run time:
> stress-ng: info:  [7670]     601.38s available CPU time
> stress-ng: info:  [7670]     368.71s user time   ( 61.31%)
> stress-ng: info:  [7670]     231.55s system time ( 38.50%)
> stress-ng: info:  [7670]     600.26s total time  ( 99.81%)
> stress-ng: info:  [7670] load average: 78.32 27.87 10.10
>

Hi Matthew,

IIUC, yes, we can reproduce it, here is the result from the server:

$ stress-ng --timeout 100 --times --verify --metrics-brief --sequential 
96 --class memory --minimize --exclude 
spawn,exec,swap,stack,atomic,bad-altstack,bsearch,context,full,heapsort,hsearch,judy,lockbus,lsearch,malloc,matrix-3d,matrix,mcontend,membarrier,memcpy,memfd,memrate,memthrash,mergesort,mincore,null,numa,pipe,pipeherd,qsort,radixsort,remap,resources,rmap,shellsort,skiplist,stackmmap,str,stream,tlb-shootdown,tree,tsearch,vm-addr,vm-rw,vm-segv,vm,wcs,zero,zlib 

stress-ng: info:  [2765] disabled 'oom-pipe' as it may hang or reboot 
the machine (enable it with the --pathological option)
stress-ng: info:  [2765] dispatching hogs: 96 tmpfs
stress-ng: info:  [2765] successful run completed in 104.67s (1 min, 
44.67 secs)
stress-ng: info:  [2765] stressor       bogo ops real time  usr time  
sys time   bogo ops/s   bogo ops/s
stress-ng: info:  [2765]                           (secs) (secs)    
(secs)   (real time) (usr+sys time)
stress-ng: info:  [2765] tmpfs               363    103.02 622.07   
7289.85         3.52         0.05
stress-ng: info:  [2765] for a 104.67s run time:
stress-ng: info:  [2765]   10047.98s available CPU time
stress-ng: info:  [2765]     622.46s user time   (  6.19%)
stress-ng: info:  [2765]    7290.66s system time ( 72.56%)
stress-ng: info:  [2765]    7913.12s total time  ( 78.75%)
stress-ng: info:  [2765] load average: 79.62 28.89 10.45

we compared the tmpfs.ops_per_sec: (363 / 103.02) between this commit 
and parent commit.

Best Regards,
Rong Chen