> wfg /tmp% g cpu log-* | g dd > log-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.26s system 9% cpu 13.658 total > log-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.26s system 9% cpu 12.961 total > log-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.26s system 9% cpu 13.420 total > log-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.30s system 9% cpu 13.103 total > log-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.31s system 9% cpu 13.650 total > log-no-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.25s system 8% cpu 15.258 total > log-no-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.26s system 8% cpu 14.255 total > log-no-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.26s system 8% cpu 14.443 total > log-no-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.25s system 8% cpu 14.051 total > log-no-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.27s system 8% cpu 14.648 total > > wfg /tmp% g cpu log-* | g tar > log-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.49s user 3.99s system 60% cpu 27.285 total > log-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.78s user 4.40s system 65% cpu 26.125 total > log-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.50s user 4.56s system 64% cpu 26.265 total > log-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.50s user 4.18s system 62% cpu 26.766 total > log-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.60s user 4.03s system 60% cpu 27.463 total > log-no-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.42s user 4.17s system 57% cpu 28.688 total > log-no-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.67s user 4.04s system 58% cpu 28.738 total > log-no-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.53s user 4.50s system 58% cpu 29.287 total > log-no-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.38s user 4.28s system 57% cpu 28.861 total > log-no-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.44s user 4.19s system 56% cpu 29.443 total Jan, here are the ext4 numbers. It's also doing better now. And I find the behaviors and hence dd vs. tar numbers are pretty different from XFS. - XFS like redirtying the inode after writing pages while ext4 not - ext4 enforces large 128MB write chunk size, while XFS uses the adaptive 24-28MB chunk size (close to half disk bandwidth) log-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.34s user 3.46s system 93% cpu 16.848 total log-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.59s user 3.30s system 95% cpu 16.655 total log-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.45s user 3.54s system 94% cpu 16.881 total log-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.62s user 3.38s system 93% cpu 17.187 total log-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.70s user 3.20s system 92% cpu 17.219 total log-no-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.48s user 3.31s system 86% cpu 18.345 total log-no-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.89s user 3.35s system 86% cpu 18.730 total log-no-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.84s user 3.41s system 86% cpu 18.820 total log-no-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.63s user 3.23s system 84% cpu 18.831 total log-no-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.76s user 3.41s system 84% cpu 19.026 total log-no-moving-expire:tar jxf /dev/shm/linux-2.6.38.3.tar.bz2 12.72s user 3.29s system 86% cpu 18.597 total log-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.71s system 9% cpu 19.019 total log-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.77s system 9% cpu 19.053 total log-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.79s system 9% cpu 19.238 total log-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.80s system 9% cpu 19.227 total log-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.76s system 9% cpu 19.439 total log-no-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.65s system 8% cpu 20.518 total log-no-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.73s system 8% cpu 20.693 total log-no-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.78s system 8% cpu 20.745 total log-no-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.72s system 8% cpu 20.369 total log-no-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.74s system 8% cpu 20.682 total log-no-moving-expire:dd if=/dev/zero of=/fs/zero bs=1M count=1000 0.00s user 1.74s system 8% cpu 20.593 total Thanks, Fengguang -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . 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