On Fri, 9 Jul 2010, Christoph Lameter wrote:
> SLUB+Q also wins against SLAB in netperf:
>
> Script:
>
> #!/bin/bash
>
> TIME=60 # seconds
> HOSTNAME=localhost # netserver
>
> NR_CPUS=$(grep ^processor /proc/cpuinfo | wc -l)
> echo NR_CPUS=$NR_CPUS
>
> run_netperf() {
> for i in $(seq 1 $1); do
> netperf -H $HOSTNAME -t TCP_RR -l $TIME &
> done
> }
>
> ITERATIONS=0
> while [ $ITERATIONS -lt 12 ]; do
> RATE=0
> ITERATIONS=$[$ITERATIONS + 1]
> THREADS=$[$NR_CPUS * $ITERATIONS]
> RESULTS=$(run_netperf $THREADS | grep -v '[a-zA-Z]' | awk '{ print $6 }')
>
> for j in $RESULTS; do
> RATE=$[$RATE + ${j/.*}]
> done
> echo threads=$THREADS rate=$RATE
> done
>
>
> Dell Dual Quad Penryn on Linux 2.6.35-rc4
>
> Loop counts: Larger is better.
>
> Threads SLAB SLUB+Q %
> 8 690869 714788 + 3.4
> 16 680295 711771 + 4.6
> 24 672677 703014 + 4.5
> 32 676780 703914 + 4.0
> 40 668458 699806 + 4.6
> 48 667017 698908 + 4.7
> 56 671227 696034 + 3.6
> 64 667956 696913 + 4.3
> 72 668332 694931 + 3.9
> 80 667073 695658 + 4.2
> 88 682866 697077 + 2.0
> 96 668089 694719 + 3.9
>
I see you're using my script for collecting netperf TCP_RR benchmark data,
thanks very much for looking into this workload for slab allocator
performance!
There are a couple differences between how you're using it compared to how
I showed the initial regression between slab and slub, however: you're
using localhost for your netserver which isn't representative of a real
networking round-robin workload and you're using a smaller system with
eight cores. We never measured a _significant_ performance problem with
slub compared to slab with four or eight cores, the problem only emerges
on larger systems.
When running this patchset on two (client and server running
netperf-2.4.5) four 2.2GHz quad-core AMD processors with 64GB of memory,
here's the results:
threads SLAB SLUB+Q diff
16 205580 179109 -12.9%
32 264024 215613 -18.3%
48 286175 237036 -17.2%
64 305309 253222 -17.1%
80 308248 243848 -20.9%
96 299845 243848 -18.7%
112 305560 259427 -15.1%
128 312668 263803 -15.6%
144 329671 271335 -17.7%
160 318737 280290 -12.1%
176 325295 287918 -11.5%
192 333356 287995 -13.6%
If you'd like to add statistics to your patchset that are enabled with
CONFIG_SLUB_STATS, I'd be happy to run it on this setup and collect more
data for you.
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