• H
    Revert "crypto: caam - get rid of tasklet" · 2b163b5b
    Horia Geantă 提交于
    This reverts commit 66d2e202.
    
    Quoting from Russell's findings:
    https://www.mail-archive.com/linux-crypto@vger.kernel.org/msg21136.html
    
    [quote]
    Okay, I've re-tested, using a different way of measuring, because using
    openssl speed is impractical for off-loaded engines.  I've decided to
    use this way to measure the performance:
    
    dd if=/dev/zero bs=1048576 count=128 | /usr/bin/time openssl dgst -md5
    
    For the threaded IRQs case gives:
    
    0.05user 2.74system 0:05.30elapsed 52%CPU (0avgtext+0avgdata 2400maxresident)k
    0.06user 2.52system 0:05.18elapsed 49%CPU (0avgtext+0avgdata 2404maxresident)k
    0.12user 2.60system 0:05.61elapsed 48%CPU (0avgtext+0avgdata 2460maxresident)k
    	=> 5.36s => 25.0MB/s
    
    and the tasklet case:
    
    0.08user 2.53system 0:04.83elapsed 54%CPU (0avgtext+0avgdata 2468maxresident)k
    0.09user 2.47system 0:05.16elapsed 49%CPU (0avgtext+0avgdata 2368maxresident)k
    0.10user 2.51system 0:04.87elapsed 53%CPU (0avgtext+0avgdata 2460maxresident)k
    	=> 4.95 => 27.1MB/s
    
    which corresponds to an 8% slowdown for the threaded IRQ case.  So,
    tasklets are indeed faster than threaded IRQs.
    
    [...]
    
    I think I've proven from the above that this patch needs to be reverted
    due to the performance regression, and that there _is_ most definitely
    a deterimental effect of switching from tasklets to threaded IRQs.
    [/quote]
    Signed-off-by: NHoria Geantă <horia.geanta@nxp.com>
    Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
    2b163b5b
jr.c 14.8 KB