On Tuesday 30 August 2011, Claudio Freire wrote:
BTW you can see that user time is 15% higher with pigz so compression per core cycle is worse.
That's called cache pressure. It happens when more than one process is running. Run four gzips concurrently, you'll probably experience the same increase.
Yes, ... ... and ouf course you will see that gzip has more throughput in any case while the system is less on load: # 4 x gzip in parallel rudi@quant:/tmp> time ( for i in `seq 1 4` ; do gzip -c hist.csv & done ;wait ) > /dev/null real 0m30.500s user 1m59.311s sys 0m0.978s # 4 x pigz in parallel in parallel rudi@quant:/tmp> time ( for i in `seq 1 4` ; do ~rudi/tmp/pigz-2.1.6/pigz -c hist.csv & done ;wait ) > /dev/null real 0m35.164s user 2m18.944s sys 0m1.236s # 4 x pigz sequential -bash: syntax error near unexpected token `)' rudi@quant:/tmp> time ( for i in `seq 1 4` ; do ~rudi/tmp/pigz-2.1.6/pigz -c hist.csv ;done ;wait ) > /dev/null real 0m35.147s user 2m16.647s sys 0m3.398s cu, Rudi -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-factory+help@opensuse.org