----- Original Message -----
From: "Paulo Henrique - BSDs" <paulo.rd...@bsd.com.br>
To: ""Lista Brasileira de Discussão sobre FreeBSD (FUG-BR)""
<freebsd@fug.com.br>
Sent: Wednesday, November 05, 2014 3:58 PM
Subject: [FUG-BR] Valor aconselhavel para variável HZ
Saudações,
Gostaria de saber se alguém trabalha com a variável HZ com o valor
superior a 2000, caso sim o ambiente fica estável, há uma melhora no
desempenho do sistema e da rede ?
Sei que a mesma interfere quanto ao uso da bateria em portáteis contudo a
duvida é restrita a servidores.
Aumentar o valor da mesma em um servidor com 12 Cores / 24 Threads com
32Gbytes de ram melhorará o desempenho.
Abaixo tem os dados do sistema atualmente.
O HZ do sistema está em 2000.
uname -a
FreeBSD xxxxx 10.0-STABLE FreeBSD 10.0-STABLE #0 r269344: Thu Jul 31
14:39:46 BRT 2014
netstat -m
yyyyyyy@xxxxx:/usr/obj/usr/src/sys/XXXXXXXXXXX amd64
11204/15571/26775 mbufs in use (current/cache/total)
1023/9825/10848/2036062 mbuf clusters in use (current/cache/total/max)
1023/9512 mbuf+clusters out of packet secondary zone in use
(current/cache)
0/548/548/1018031 4k (page size) jumbo clusters in use
(current/cache/total/max)
0/0/0/301638 9k jumbo clusters in use (current/cache/total/max)
0/0/0/169671 16k jumbo clusters in use (current/cache/total/max)
4847K/25734K/30581K bytes allocated to network (current/cache/total)
0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
0/0/0 requests for mbufs delayed (mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters delayed (4k/9k/16k)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
0 requests for sfbufs denied
0 requests for sfbufs delayed
9966280 requests for I/O initiated by sendfile
uptime
15:47 up 86 days, 19:40, 1 user, load averages: 8,15 8,86 9,27
Alguns tunnings que já foi feito no sistema.
# $FreeBSD: stable/10/etc/sysctl.conf 112200 2003-03-13 18:43:50Z mux $
#
# This file is read when going to multi-user and its contents piped thru
# ``sysctl'' to adjust kernel values. ``man 5 sysctl.conf'' for details.
#
# Uncomment this to prevent users from seeing information about processes
that
# are being run under another UID.
#security.bsd.see_other_uids=0
kern.maxfiles=1000000
# Otimizacoes de rede.
#kern.ipc.nmbclusters=131072 # 128Mb para buffer de rede - Ficou instavel
valor definido pelo sistema.
kern.ipc.maxsockbuf=33554432
net.inet.tcp.sendbuf_max=33554432
net.inet.tcp.recvbuf_max=33554432
net.inet.tcp.sendspace=1048576 # default 65536
net.inet.tcp.recvspace=1048576 # default 32768
net.inet.tcp.sendbuf_inc=1048576 # 8192 default
net.inet.tcp.recvbuf_inc=1048576 # 16384 default
kern.ipc.somaxconn=4096 # 128 default
net.inet.tcp.syncache.rexmtlimit=1
net.inet.tcp.syncookies=1
# COnfigura▒▒es de Seguran▒a
# General Security and DoS mitigation.
net.inet.ip.check_interface=1 # verify packet arrives on correct interface
net.inet.ip.portrange.randomized=1 # randomize outgoing upper ports
net.inet.ip.process_options=0 # IP options in the incoming packets will be
ignored
net.inet.ip.random_id=1 # assign a random IP_ID to each packet leaving the
system
net.inet.ip.redirect=0 # do not send IP redirects
net.inet.ip.accept_sourceroute=0 # drop source routed packets since they
can not be trusted
net.inet.ip.sourceroute=0 # if source routed packets are accepted the
route data is ignored
#net.inet.ip.stealth=1 # do not reduce the TTL by one(1) when a packets
goes through the firewall
net.inet.icmp.bmcastecho=0 # do not respond to ICMP packets sent to IP
broadcast addresses
net.inet.icmp.maskfake=0 # do not fake reply to ICMP Address Mask Request
packets
net.inet.icmp.maskrepl=0 # replies are not sent for ICMP address mask
requests
net.inet.icmp.log_redirect=0 # do not log redirected ICMP packet attempts
net.inet.icmp.drop_redirect=1 # no redirected ICMP packets
#net.inet.icmp.icmplim=50 # 50 ICMP packets per second. a reasonable
number for a small office.
#net.inet.tcp.delayed_ack=1 # always employ delayed ack, 6 packets get 1
ack to increase bandwidth
net.inet.tcp.drop_synfin=1 # SYN/FIN packets get dropped on initial
connection
net.inet.tcp.ecn.enable=1 # explicit congestion notification (ecn)
warning: some ISP routers abuse it
net.inet.tcp.fast_finwait2_recycle=1 # recycle FIN/WAIT states quickly
(helps against DoS, but may cause false RST)
net.inet.tcp.icmp_may_rst=0 # icmp may not send RST to avoid spoofed
icmp/udp floods
net.inet.tcp.maxtcptw=15000 # max number of tcp time_wait states for
closing connections
net.inet.tcp.msl=5000 # 5 second maximum segment life waiting for an ACK
in reply to a SYN-ACK or FIN-ACK
net.inet.tcp.path_mtu_discovery=0 # disable MTU discovery since most ICMP
packets are dropped by others
net.inet.tcp.rfc3042=0 # disable the limited transmit mechanism which can
slow burst transmissions
#net.inet.tcp.sack.enable=1 # sack disabled?
http://www.ibm.com/developerworks/linux/library/l-tcp-sack/index.html
net.inet.udp.blackhole=1 # drop udp packets destined for closed sockets
net.inet.tcp.blackhole=2 # drop tcp packets destined for closed ports
#net.route.netisr_maxqlen=4096 # route queue length defaults 4096 (rtsock
using "netstat -Q")
security.bsd.see_other_uids=0 # hide processes for root from user uid's
## Configuracoes de envio
net.local.stream.sendspace=164240
net.local.stream.recvspace=164240
## Configuracoes contra spoof
net.inet.ip.rtexpire=60 # 3600 secs
net.inet.ip.rtminexpire=2 # 10 secs
net.inet.ip.rtmaxcache=1024 # 128 entries
Qualquer orientação é bem vinda.
Ate o FreeBSD 7 eu ate que me preocupava em ficar mexendo no hz. Apos isto,
e com estas interfaces de rede modernas da Intel, nao me preocupo mais (nem
com hz nem com polling) pois PARECE nao mudar muito coisa.
Veja uma discussao de 2005 sobre o hz onde ja se discutia isto:
http://lists.freebsd.org/pipermail/freebsd-questions/2005-April/083482.html
e veja tambem este link, na parte onde esta o hz o que ele diz:
https://calomel.org/freebsd_network_tuning.html
Edinilson
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