SPECweb99 Tuning Disclosure: For Digital UNIX 5.1A
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Sysconfigtab Parameters:
proc:
max-per-proc-address-space -
max-per-proc-data-size -
Maximum values for the current limits of the attributes
per-proc-address-space and per-proc-data-size. The current limits can be
increased at run time by means of the setrlimit(2) system call or the
ulimit(3) C library call. The current limits cannot be expanded beyond the
values established by the "max-per-proc-*" attributes.
Default value: max-per-proc-address-space = 1073741824
max-per-proc-data-size = 4398046511104
max-proc-per-user -
The maximum limit of processes (tasks) a user can create. Zero indicates
unlimited. (The superuser is not affected.) Default value: 64
max-threads-per-user -
The maximum limit of threads a user can create. (The superuser is not
affected.) Default value: 256
per-proc-address-space -
per-proc-data-size -
The current upper limits of the respective resources. For example, a user
address space cannot exceed the size set by the per-proc-address-space
attribute.
Default value: per-proc-address-space = 1073741824
per-proc-data-size = 4398046511104
socket:
umc - Enables (1) or disables (0) the Unified Mbuf Cache (UMC)
Default value: 0
sominconn -
Minimum value for socket listen queue length limit (backlog). Silently
overrides user-specified backlog when the user backlog is less than than
the value of this attribute. Takes precedence over the somaxconn attribute.
Default value: 0
somaxconn -
Maximum value for socket listen queue length limit (backlog). Silently
overrides user-specified backlog when the user backlog is greater than the
value of this attribute. The sominconn attribute takes precedence.
Default value: 1024
inet:
ipqmaxlen - Maximum length of the IP input queue (ipintrq) before input
packets are dropped.
Default value: 1024 (bytes)
ipqs - Number of IP processing queues. Default value: 1
tcbhashnum - Number of primary TCP hash table entries. Default value: 1
tcbhashsize -
Sets the TCP control block hash table size. Default value: 32
tcp_sendspace - Default send buffer size, in bytes, for TCP sockets.
Default value: 61440 (bytes)
net:
netisrthreads - Number of network threads configured in a system.
Default value: n (Based on the number of CPUs in a system.
netisrwakeupthreshold - Number of packets (packet threshold) above which
another netisr thread is started.
Default value: 1 (packet)
vm:
vm_swap_eager - Specifies the swap allocation mode, which can be immediate
mode (1) or deferred mode (0).
Default value: 1 (immediate mode)
vfs:
name-cache-hash-size
Size of the hash chain table for the namei cache. Default value: 256 slots
namei-cache-valid-time
Amount of time a namei cache entry can remain in the cache before it is
discarded. Default value: 1200 (seconds)
advfs:
AdvfsCacheMaxPercent - The percentage of system memory that is allocated to
the AdvFS buffer cache, which stores file data.
Default value: 7 (percent)
AdvfsCacheHashSize - Size of hash table for Advfs buffer cache. Default
based on AdvfsCacheMaxPercent.
alt:
minimal_isr
A value that enables (1) or disables (0) the awakening of separate
threads by the driver's interrupt service routine to handle completion
of transmit and receive operations. When separate worker threads are
enabled, the system load of the Gigabit Ethernet driver can be spread
over multiple CPUs. When separate worker threads are disabled, the mas-
ter system CPU (or the master CPU in each RAD of a NUMA system) ser-
vices all the transmit and receive operations for the system's Gigabit
Ethernet adapters. Default: 1 (multiple threads enabled)
recv_coal
The number of packets that are sent before an interrupt is generated
(assuming that the recv_ticks timer does not expire first).
Default: 32 (packets)
recv_ticks
The number of microseconds (usec) that elapse after receipt of the last
packet before an interrupt is generated (assuming that the recv_coal
threshold is not reached first). Default: 200 (usec)
send_coal
The number of packets that are sent before an interrupt is generated
(assuming that the send_ticks timer does not expire first).
Default: 32 (packets)
send_ticks
The number of microseconds (usec) that elapse after transmission of the
last packet before an interrupt is generated (assuming that the
send_coal threshold is not reached first). Default: 125,000 (usec)
Kernel (vmunix) tuning using Spike:
Spike is a tool that performs feedback-based code optimization on programs.
To optimize the kernel a profile was taken using the Continuous Profiling
Infrastructure (DCPI) tool while running a static HTTP workload
(DYNAMIC_CONTENT=0, USER_LINE_SPEED=200000, USER_SPEED_LIMIT=160000).
Commands used:
dcpid -vkprof -vtrace /usr/lib/dcpi/vp-ldlatency.so /usr/users/spec/DCPI/dcpidb
sleep 300
dcpiquit
dcpi2bb -make_bbdb -counts -pm all -conf_low -load_lat -epoch latest vmunix
spike -kernel vmunix -o vmunix_spike -feedback vmunix -splitThresh .999 \
-optThresh .999
Zeus 3.3 Tuning:
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For details on the Zeus tuning parameters used please see:
http://support.zeus.co.uk/faq/entries/ful.html#tuning.html
The following tunables are the Zeus global parameters (global.cfg)
used in Compaq Alphaserver results:
tuning!bind_any
Boolean: have server sockets bind to IPADDR_ANY default = yes
tuning!cache_files
Size of the web server file cache (number of files) default = 8011
tuning!cache_flush_interval
Time after which unaccessed files are flushed from
the cache (seconds) default = 120
tuning!cache_large_file
Minimum size of a "large" file (bytes) default = 1048577
tuning!cache_max_bytes
Maximum size to reserve for cached files (bytes)
(0=nolimit) default = 33554432
tuning!cache_small_file
Maximum size of a "small"file (bytes) (system
page size) default = 4096
tuning!cache_stat_expire
Time for which the response of a stat() call
is cached (seconds) default = 17
tuning!num_children
Number of child zeus.web processes to run independent
of the number of CPUs (the default, however, is set to
1 per CPU initially) default = <#cpus>
tuning!so_wbuff_size
Size of the socket write buffer (bytes) default = <unset>
tuning!softservers
Enable 'software' virtual servers default = yes
tuning!unique_bind
Force each child process to bind to a unique IP
address, and not to each interface default = no
tuning!use_poll
Boolean: use poll() instead of select() default = yes
tuning!cache_cooling_time
Zeus imposed delay before caching recently modified
files starts (seconds) default = 120
tuning!cbuff_size
Integer: cgi buffer size default = 8192