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author | bde <bde@FreeBSD.org> | 1996-06-17 12:43:04 +0000 |
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committer | bde <bde@FreeBSD.org> | 1996-06-17 12:43:04 +0000 |
commit | 501044728620e5a296b82f0ab2bae44a27b2d661 (patch) | |
tree | 3f63b260207bfa855155aa2238d005e661846b33 /sys/kern/subr_diskslice.c | |
parent | 0a87e3a7fa8817e4601100fc52862340c63c099e (diff) | |
download | FreeBSD-src-501044728620e5a296b82f0ab2bae44a27b2d661.zip FreeBSD-src-501044728620e5a296b82f0ab2bae44a27b2d661.tar.gz |
In microtime(), use pushfl/popfl to preserve the interrupt enable flag
instead of sti to it restore to its usual state. pushfl/popfl is
actually faster in protected mode on Pentiums (4+3 cycles instead of 9),
and using sti made it extremely inconvenient to call microtime() from
fast interrupt handlers. pushfl/popfl is a couple of cycles slower than
sti on 486's and a couple more cycles slower on 386's, but the relative
cost of using it is not large since microtime() has to use slow i/o
instructions on the old cpus.
Diffstat (limited to 'sys/kern/subr_diskslice.c')
0 files changed, 0 insertions, 0 deletions