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Cpu usage diagnose

Top 10 processes most recently on the CPU, generally this is USer time
# ps -fe | sort -nk4 | tail

Top 20 kernel processes most recently on the CPU, generally this is SYstem time
# ps -fk | sort -nk4 | grep -v -e wait -e sched -e swapper | tail -22

Biggest Kernel offenders I see are generally, lrud, j2pg, vtiol.
LRUD = Scanning for free memory and freeing pages. Can be tuned.
J2PG = I think is something to do with JFS2 pages. Maybe something to do
with seaching the JFS2 cache for pages and/or reading JFS2 pages (pageIn/Out).
VTIOL = Something to do with offloading iodones from the adapter to the CPU.

# Top 20 Kernel and User processes who have consumed the most CPU since process started.
# ps guw | head -22

Anúncios
Categorias:AIX, Miscelânea, Performance

Debug de IO para identificar processo com IO wait alto.

janeiro 6, 2014 Deixe um comentário

Habilite o debug de IO

echo 1 > /proc/sys/vm/block_dump

Depois disso devemos verificar com o comando dmesg

dmesg | egrep “READ|WRITE|dirtied” |  awk ‘{print $1}’|  sort | uniq -c | sort -rn | head

1583 kjournald(1234)
545 kjournald(1089):
48 beam.smp.trap(21056):
47 cupsd(20882):
28 oracle(20758):

Desconsiderar processos do kernel e verificar somente os de camada de usuário.

Desabilitar o dump logo em seguida.
echo 0 > /proc/sys/vm/block_dump

Categorias:LINUX, Performance Tags:,