Prev: fs: fat: use hex_asc_lo/hex_asc_hi instead of custom one
Next: lock's trace events can improve mutex's performance in userspace?
From: Mike Galbraith on 11 Mar 2010 04:50
Hi Peter,

The following patchlets take a pinned pipe-test context switch frequency
in tip from 663KHZ to 694KHZ, and an unpinned instance from 450KHz to
540KHz. With these applied to tip.today, I have zero 31-12->today
regressions, and even some modest progressions.

The biggest difference is made by the first patch. We have a problem
with nohz when waking cross-cpu, which given select_idle_sibling(), we
do quite a bit. In testing netperf TCP_RR, hitting nohz code on every
micro-idle was eating ~10% of throughput, making cross-cpu wakeup a
loser. These patchlets combined turned netperf TCP_RR cross-cpu vs
affine from big loser into a winner.

All of these are trivial, mostly axe murder, but cycles add up.

-Mike

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
 | 
Pages: 1
Prev: fs: fat: use hex_asc_lo/hex_asc_hi instead of custom one
Next: lock's trace events can improve mutex's performance in userspace?