Re: CSCAN vs CFQ I/O scheduler benchmark results

[Jan Engelhardt <jengelh@linux01.gwdg.de>]

> The previous mail got scrambbled and hence I am resending this one
> again
>
Still. Here are the values, fit for 80 cols.

			Latency (seconds)
			CFQ	CSCAN
	seq reads	0.0116	0.0148
	seq writes	0.0164	0.0092
	seq r+w		0.0107	0.0169
	rnd reads	0.1178	0.1043
	rnd writes	0.0423	0.0473
	rnd r+w		0.0605	0.0732

			Throughput MB/sec
			CFQ	CSCAN
	seq reads	19.062	14.553
	seq writes	15.251	22.108
	seq r+w		22.127	14.72
	rnd reads	2.1197	2.394
	rnd writes	1.0032	0.9304
	rnd r+w		1.376	1.399

Excels at sequential writes, so it seems like a good idea to use CSCAN on a 
target drive when doing `rsync disk1/ disk2/`, esp. for large 
files.



Jan Engelhardt
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