Re: zram: per-cpu compression streams

[Minchan Kim <minchan@kernel.org>]

Hello Sergey,

On Sat, Apr 02, 2016 at 12:38:29AM +0900, Sergey Senozhatsky wrote:
> Hello Minchan,
> 
> On (03/31/16 15:34), Sergey Senozhatsky wrote:
> > > I tested with you suggested parameter.
> > > In my side, win is better compared to my previous test but it seems
> > > your test is so fast. IOW, filesize is small and loops is just 1.
> > > Please test filesize=500m loops=10 or 20.
> 
> fio
> - loops=10
> - buffer_pattern=0xbadc0ffee
> 
> zram 6G. no intel p-state, deadline IO scheduler, no lockdep (no lock debugging).

We are using rw_page so I/O scheduler is not related.
Anyway, I configured my machine as you said but still see 10~20% enhance. :(
Hmm, could you post your .config?
I want to investigate why such difference happens between our machines.

The reason I want to see such *big enhance* in my machine is that
as you know, with per-cpu, zram's write path will lose blockable section
so it would make upcoming features's implementation hard.

We also should test it in very low memory situation so every write path
retry it(i.e., dobule compression). With it, I want to see how many
performance can drop.

If both test(normal: huge win low memory: small regression) are fine,
we can go per-cpu approach at the cost of giving up blockable section.
:)

Thanks.


> 
> 
> test            8 streams        per-cpu
> 
> #jobs1                         	                
> READ:           4118.2MB/s	 4105.3MB/s
> READ:           3487.7MB/s	 3624.9MB/s
> WRITE:          2197.8MB/s	 2305.1MB/s
> WRITE:          1776.2MB/s	 1887.5MB/s
> READ:           736589KB/s	 745648KB/s

> WRITE:          736353KB/s	 745409KB/s
> READ:           679279KB/s	 686559KB/s
> WRITE:          679093KB/s	 686371KB/s
> #jobs2                         	                
> READ:           6924.6MB/s	 7160.2MB/s
> READ:           6213.2MB/s	 6247.1MB/s
> WRITE:          2510.3MB/s	 3680.1MB/s
> WRITE:          2286.2MB/s	 3153.9MB/s
> READ:           1163.1MB/s	 1333.7MB/s
> WRITE:          1163.4MB/s	 1332.2MB/s
> READ:           1122.9MB/s	 1240.3MB/s
> WRITE:          1121.9MB/s	 1239.2MB/s
> #jobs3                         	                
> READ:           10304MB/s	 10424MB/s
> READ:           9014.5MB/s	 9014.5MB/s
> WRITE:          3883.9MB/s	 5373.8MB/s
> WRITE:          3549.1MB/s	 4576.4MB/s
> READ:           1704.4MB/s	 1916.8MB/s
> WRITE:          1704.9MB/s	 1915.9MB/s
> READ:           1603.5MB/s	 1806.8MB/s
> WRITE:          1598.8MB/s	 1800.8MB/s
> #jobs4                         	                
> READ:           13509MB/s	 12792MB/s
> READ:           10899MB/s	 11434MB/s
> WRITE:          4027.2MB/s	 6272.8MB/s
> WRITE:          3902.1MB/s	 5389.2MB/s
> READ:           2090.9MB/s	 2344.4MB/s
> WRITE:          2085.2MB/s	 2337.1MB/s
> READ:           1968.1MB/s	 2185.9MB/s
> WRITE:          1969.5MB/s	 2186.4MB/s
> #jobs5                         	                
> READ:           12634MB/s	 11607MB/s
> READ:           9932.7MB/s	 9980.6MB/s
> WRITE:          4275.8MB/s	 5844.3MB/s
> WRITE:          4210.1MB/s	 5262.3MB/s
> READ:           1995.6MB/s	 2211.4MB/s
> WRITE:          1988.4MB/s	 2203.4MB/s
> READ:           1930.1MB/s	 2191.8MB/s
> WRITE:          1929.8MB/s	 2190.3MB/s
> #jobs6                         	                
> READ:           12270MB/s	 13012MB/s
> READ:           11221MB/s	 10815MB/s
> WRITE:          4643.4MB/s	 6090.9MB/s
> WRITE:          4373.6MB/s	 5772.8MB/s
> READ:           2232.6MB/s	 2358.4MB/s
> WRITE:          2233.4MB/s	 2359.2MB/s
> READ:           2082.6MB/s	 2285.8MB/s
> WRITE:          2075.9MB/s	 2278.1MB/s
> #jobs7                         	                
> READ:           13617MB/s	 14172MB/s
> READ:           12290MB/s	 11734MB/s
> WRITE:          5077.3MB/s	 6315.7MB/s
> WRITE:          4719.4MB/s	 5825.1MB/s
> READ:           2379.8MB/s	 2523.7MB/s
> WRITE:          2373.7MB/s	 2516.7MB/s
> READ:           2287.9MB/s	 2362.4MB/s
> WRITE:          2283.9MB/s	 2358.2MB/s
> #jobs8                         	                
> READ:           15130MB/s	 15533MB/s
> READ:           12952MB/s	 13077MB/s
> WRITE:          5586.6MB/s	 7108.2MB/s
> WRITE:          5233.5MB/s	 6591.3MB/s
> READ:           2541.2MB/s	 2709.2MB/s
> WRITE:          2544.6MB/s	 2713.2MB/s
> READ:           2450.6MB/s	 2590.7MB/s
> WRITE:          2449.4MB/s	 2589.3MB/s
> #jobs9                         	                
> READ:           13480MB/s	 13909MB/s
> READ:           12389MB/s	 12000MB/s
> WRITE:          5266.8MB/s	 6594.9MB/s
> WRITE:          4971.6MB/s	 6442.2MB/s
> READ:           2464.9MB/s	 2470.9MB/s
> WRITE:          2482.7MB/s	 2488.8MB/s
> READ:           2171.9MB/s	 2402.2MB/s
> WRITE:          2174.9MB/s	 2405.5MB/s
> #jobs10                        	                
> READ:           14647MB/s	 14667MB/s
> READ:           11765MB/s	 12032MB/s
> WRITE:          5248.7MB/s	 6740.4MB/s
> WRITE:          4779.8MB/s	 5822.8MB/s
> READ:           2448.8MB/s	 2585.3MB/s
> WRITE:          2449.4MB/s	 2585.9MB/s
> READ:           2290.5MB/s	 2409.1MB/s
> WRITE:          2290.2MB/s	 2409.7MB/s
> 
> 	-ss