Difference between revisions of "OS: Tuning Kernel Scheduler"

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−
Sumber: http://www.techtinker.com/linux/LinuxKernel.html#HowRedHat
+
==Mengapa tune kernel?==
 +
 
 +
Perilaku default kernel UNIX biasanya tidak optimal karena sulit untuk mengantisipasi jenis pekerjaan atau beban kerja yang akan diberikan kepada sistem operasi . Oleh karena itu, UNIX menyediakan parameter yang dapat mengubah alokasi sumber daya. Parameter kernel tuning adalah spesifik UNIX.
 +
 
 +
Administrator sistem bertanggung jawab untuk menentukan jenis target pekerjaan dan beban kerja untuk mesin dan untuk memantau apakah terjadi perubahan dari waktu ke waktu. Administrator sistem harus memastikan bahwa setiap parameter kernel diatur untuk mengoptimalkan kinerja mesin.
 +
 
 +
CATATAN: Tuning Kernel merupakan topik lanjut dan tidak boleh dilakukan tanpa pemahaman lengkap tentang hal tersebut.
 +
 
 +
==Kernel tuning with sysctl==
 +
 
 +
Sumber: http://archive09.linux.com/feature/146599
 +
Oleh Federico Kereki 9 September 2008 (4:00:00 PM)
 +
 
 +
Kernel Linux cukup fleksibel, kita bahkan dapat memodifikasi cara kerjanya sambil komputer jalan secara dinamis mengubah beberapa parameter, berkat perintah sysctl. Sysctl menyediakan sebuah antarmuka yang memungkinkan kita untuk memeriksa dan mengubah ratusan parameter kernel di Linux atau BSD. Perubahan segera berlaku, dan bahkan ada cara untuk membuat parameter tersebut tidak hilang setelah reboot. Dengan menggunakan sysctl secara bijak, kita dapat mengoptimalkan komputer tanpa harus mengkompilasi ulang kernel , dan mendapatkan hasilnya dengan cepat.
 +
 
 +
Untuk mendapatkan sedikit rasa parameter apa saja yang dapat di modifikasi oleh sysctl, jalankan sysctl -a
 +
 
 +
$ sysctl -a
 +
 
 +
Hasilnya
 +
 
 +
kernel.sched_child_runs_first = 0
 +
kernel.sched_min_granularity_ns = 1500000
 +
kernel.sched_latency_ns = 12000000
 +
kernel.sched_wakeup_granularity_ns = 2000000
 +
kernel.sched_tunable_scaling = 1
 +
kernel.sched_migration_cost = 500000
 +
kernel.sched_nr_migrate = 32
 +
kernel.sched_time_avg = 1000
 +
kernel.sched_shares_window = 10000000
 +
kernel.timer_migration = 1
 +
kernel.sched_rt_period_us = 1000000
 +
kernel.sched_rt_runtime_us = 950000
 +
kernel.sched_autogroup_enabled = 1
 +
kernel.sched_cfs_bandwidth_slice_us = 5000
 +
kernel.panic = 0
 +
... dan seterusnya ...
 +
 
 +
Jika kita ingin mendapatkan nilai hanya satu variabel, gunakan perintah seperti
 +
 
 +
sysctl vm.swappiness
 +
 
 +
atau hanya
 +
 
 +
sysctl vm
 +
 
 +
untuk daftar semua variabel yang dimulai dengan "vm." Tambahkan opsi -n untuk mengeluarkan hanya nilai variabel, tanpa nama,-N memiliki efek sebaliknya, dan menghasilkan nama-nama tapi tidak nilai.
 +
 
 +
Kita dapat mengubah nlai variabel dengan menggunakan opsi-w dengan sintaks
 +
 
 +
sysctl -w variable=nilai
 +
 
 +
Misalnya,
  
 +
sysctl -w net.ipv6.conf.all.forwarding=1
  
 +
set variabel menjadi benar / true (0 sama dengan "tidak" atau "salah", 1 berarti "ya" atau "benar") sehingga memungkinkan IP6 forwarding. Anda mungkin tidak membutuhkan opsi -w tampaknya akan usang.
  
−
    What is a kernel?
+
Informasi lebih lanjut tentang sysctl dapat di baca dengan cara mengetik
  
−
    A UNIX kernel is an interpreter that translates user level system calls into synchronized access to hardware and device drivers. The calls are defined by POSIX standards.
+
man sysctl
  
−
    The interpreter manages user level requests for file or process access. The kernel's scheduler enables UNIX to juggle file and process subsystems. The file subsystem works with raw or block disk devices. The process subsystem manages process synchronization, inter-process communication, memory management and process scheduling.
 
  
−
    The kernel manages through the use of two key structures, the process table and the user structure. The process table contains scheduling parameters, memory image, signals and miscellaneous process states. The user structure includes machine registries, system call state, file descriptor table, accounting and kernel stack.
+
===sysctl dan directory /proc===
  
−
    Why tune a kernel?
+
Virtual directory /proc/sys juga memberikan interface ke parameter sysctl memungkinkan kita untuk melihat dan mengubah parameter tersebut. Contoh, file  /proc/sys/vm/swappiness sama dengan parameter vm.swappiness parameter di sysctl.conf. Oleh karenanya, melakukan
  
−
    The default UNIX kernel behavior is suboptimal out of the box because it is difficult to anticipate what type of work or workload the operating system will be assigned. Therefore, UNIX products provide parameters that may change the allocation of critical resources. The kernel tuning parameters are UNIX product specific.
+
echo 10 >/proc/sys/vm/swappiness
  
−
    The system administrator is responsible to determine the target type of work and workload for a machine and to monitor whether either change over time. The system administrator should ensure that any tunable kernel parameters are set to optimize machine performance.
+
sama dengan
  
−
        NOTE:
+
sysctl -w vm.swappiness=10
−
        Kernel tuning is an advanced topic and should not be done without a complete understanding of the subject.
 
  
−
    How to tune Red Hat?
+
Yang perlu kita perhatikan, jika file /proc/sys read-only, maka kita tidak akan bisa mengubahnya juga dengan sysctl.
  
−
    The super user should configure the tunable parameters for the Red Hat Application Server 2.1 Linux kernel before installing Oracle9i or Oracle Applications 11i. If using an Oracle Development Services slot, the concurrent number of Oracle9i and Oracle 9iAS instances should be determined. The number of concurrent instances will enable validating whether the tunable kernel parameters are correctly configured.
+
Tulis
  
−
        Edit the /etc/sysctl.conf file.
+
ls /proc/sys/kernel
  
−
        The changes noted below should be made in the /etc/sysctl.conf file. If using a slot, log a bug to effect changes to a slot environment. Copy the following from the web page into the /etc/sysctl.conf file. Recalculate the numeric values and use the new values to edit the file.
+
untuk melihat parameter kernel yang bisa kita ubah.
  
−
        # -------------------------------------------------------------------------
+
===sysctl.conf===
−
        # Kernel parameter assumptions and rationale.
 
−
        # ===========================================
 
−
        #
 
−
        # Linux Advanced Server 2.1 has a configure restricted kernel.
 
−
        #
 
−
        # -------------------------------------------------------------------------
 
−
        # Disables packet forwarding
 
−
        # -------------------------------------------------------------------------
 
  
−
        net.ipv4.ip_forward = 0
+
Nilai paramter sysctl akan di load dari file /etc/sysctl.conf saat boot. File ini dapat memiliki baris kosong, komen (start dengan #), dan baris dengan format "variable=nilai" format. Contoh isi sysctl.conf adalah sebagai berikut,
  
−
        # -------------------------------------------------------------------------
+
# Disable response to broadcasts.
−
        # Enables source route verification
+
net.ipv4.icmp_echo_ignore_broadcasts = 1
−
        # -------------------------------------------------------------------------
+
 +
# enable route verification on all interfaces
 +
net.ipv4.conf.all.rp_filter = 1
 +
 +
# enable ipV6 forwarding
 +
net.ipv6.conf.all.forwarding = 1
 +
 +
# increase the number of possible inotify(7) watches
 +
fs.inotify.max_user_watches = 65536
  
−
        net.ipv4.conf.default.rp_filter = 1
+
Jika kita ingin mengaktifkan / mereload parameter sysctl, dapat dilakukan dengan perintah
  
−
        # -------------------------------------------------------------------------
+
sysctl -p.
−
        # Set the default local port range.
 
−
        # -------------------------------------------------------------------------
 
  
−
        net.ipv4.ip_local_port_range = 1024 65000
 
  
−
        # -------------------------------------------------------------------------
 
−
        # Enables the magic-sysrq key
 
−
        # -------------------------------------------------------------------------
 
  
−
        kernel.sysrq = 1
+
Sumber: http://www.techtinker.com/linux/LinuxKernel.html#HowRedHat
  
−
        # -------------------------------------------------------------------------
 
−
        # General semaphore rules:
 
−
        # -----------------------
 
−
        # 1. Semaphore tunable parameters are limited to semmsl, semmns,
 
−
        #    semopm and semmni and must be entered in the /etc/sysctl.conf
 
−
        #    file with the following syntax.
 
−
        #
 
−
        #    kernel.sem = semmsl semmns semopm semmni
 
−
        #
 
−
        # 2. The tunable kernel resource of semmsl sets the maximum number
 
−
        #    of semaphore per set. The semopm should be set equal to semmsl
 
−
        #    so that an operation can be performed on every semaphore in
 
−
        #    the set. If semopm is larger than semmsl it should raise an
 
−
        #    OS exception but doesn't in Linux.
 
−
        #
 
−
        #    Oracle8i Installation Manual for UNIX recommends this value be
 
−
        #    derived as "... the sum of the PROCESSES parameter for each
 
−
        #    Oracle database except the largest one, plus 2 times the largest
 
−
        #    PROCESSES value, plus 10 times the number of Oracle databases."
 
−
        #    Assuming 2 Oracle8i databases with the init{SID}.ora "processes"
 
−
        #    parameter set to 100 and 1 Oracle 9iAS server with "processes"
 
−
        #    parameter set to 100, the following is the recommended value:
 
−
        #
 
−
        #    Variables:
 
−
        #    =========
 
−
        #    s = sum of processes for all but largest instance
 
−
        #    m = maximum number of process for a single instance
 
−
        #    n = total number of instances
 
−
        #    i = n - largest instance.
 
−
        #
 
−
        #    semmsl = ((s * i) + (m * 2)) + (n * 10))
 
−
        #
 
−
        #    semmsl = ((100*2) + (100)*2) + (3 * 10)) = (400 + 30) = 430
 
−
        #
 
−
        #    semopm = semmsl = 430
 
−
        #
 
−
        # 3. The tunable kernel resource of semmni sets the system wide
 
−
        #    semaphore sets by creating a semid_ds control structure of
 
−
        #    84 bytes, so this parameter should not be set arbitrarily large.
 
−
        #    The Oracle8i and Oracle9i installation manual recommends 100
 
−
        #    for each Oracle instance. Assuming 2 Oracle8i databases with
 
−
        #    the init{SID}.ora processes parameter set to 100 and 1 Oracle
 
−
        #    9iAS server with processes parameter set to 100, the following
 
−
        #    is the recommended value:
 
−
        #
 
−
        #    semmni = 300
 
−
        #
 
−
        # 4. The semmsl (maximum number of semaphores per identifier) value
 
−
        #    is the product of the semmni and semmsl values, as qualified
 
−
        #    below:
 
−
        #
 
−
        #    semmns = (semmni * semmsl) = 300 * 430 = 129000
 
−
        #
 
−
        # 5. Therefore, semaphores should be set in the /etc/sysctl.conf
 
−
        #    file as follows:
 
−
        # -------------------------------------------------------------------------
 
  
−
        kernel.sem = 430 129000 430 300
+
==Contoh Tuning Kernel untuk Oracle9i==
  
−
        # -------------------------------------------------------------------------
+
Contoh berikut adalah tuning Linux Kernel sebelum menginstalasi Oracle9i atau Oracle Applications 11i.
−
        # General semaphore rules:
 
−
        # -----------------------
 
−
        # 1. The "Oracle9i Installation Guide, Release 2 (9.2.0.1.0) for
 
−
        #    UNIX Systems: AIX-Based Systems, Compaq Tru64 UNIX, HP 9000
 
−
        #    Series HP-UX, Linux Intel, and Sun Solaris" manual (A96167)
 
−
        #    advises default settings for shmmin, shmmni, shmseg and
 
−
        #    shmvmx shared memory kernel values.
 
−
        #
 
−
        # 2. The shmmin should be set to 1.
 
−
        #
 
−
        # 3. The shmmni memory variable sets the maximum number of
 
−
        #    system wide shmid_ds structures and should be equal to the
 
−
        #    value determined for semmni value.
 
−
        #
 
−
        #    shmmni = semmni = 300
 
−
        #
 
−
        # 4. The shmmax should be set to 50% of available memory or 2 GB but
 
−
        #    setting above 50% of available memory can cause some memory use
 
−
        #    issues in Oracle8i.
 
−
        #
 
−
        # 5. The shmmin, shmmsg and shmvmx cannot be set when using the
 
−
        #    Red Hat Advanced Server 2.1 because alteration of the kernel is
 
−
        #    not supported by Oracle and these typically tunable parameters
 
−
        #    are fixed in the supported and shipped kernels.
 
−
        #
 
−
        # -------------------------------------------------------------------------
 
  
−
        kernel.shmmni = 300
+
Edit file /etc/sysctl.conf
−
        kernel.shmmax = 2147483648
 
  
−
        # -------------------------------------------------------------------------
+
vi /etc/sysctl.conf
−
        # General File Management:
 
−
        # -----------------------
 
−
        # The default value of 8192 is not compatible with Oracle's file limit
 
−
        # of 65536 and should be changed to that value or higher provided memory
 
−
        # is available. For example, the typical rule-of-thumb is to divide real
 
−
        # memory by 16,384, or 64 simultaneous open files per 1 MB of memory.
 
−
        # In systems with large amounts of memory, concurrency of file access
 
−
        # would be a better rule-of-thumb. The value is set based on 2 GB of
 
−
        # real memory as follows below.
 
−
        #
 
−
        #    fs.file-max = ( 2,097,152,000 / 16384 ) = 128,000
 
−
        #
 
−
        # Using the 2.2.x Linux kernel you will need to set the inode-max
 
−
        # value to 4 to 5 times the file-max value. However, beginning with the
 
−
        # 2.4.x Linux kernel inode-max is managed dynamically and should not be
 
−
        # set in the /etc/sysctl.conf file.
 
−
        # -------------------------------------------------------------------------
 
  
−
        fs.file-max=128000
+
Contoh konfigurasi
  
−
        Reboot to effect the changes.
+
# -------------------------------------------------------------------------
 +
# Kernel parameter assumptions and rationale.
 +
# ===========================================
 +
 +
# -------------------------------------------------------------------------
 +
# Disables packet forwarding
 +
# -------------------------------------------------------------------------
 +
 +
net.ipv4.ip_forward = 0
 +
 +
# -------------------------------------------------------------------------
 +
# Enables source route verification
 +
# -------------------------------------------------------------------------
 +
 +
net.ipv4.conf.default.rp_filter = 1
 +
 +
# -------------------------------------------------------------------------
 +
# Set the default local port range.
 +
# -------------------------------------------------------------------------
 +
 +
net.ipv4.ip_local_port_range = 1024 65000
 +
 +
# -------------------------------------------------------------------------
 +
# Enables the magic-sysrq key
 +
# -------------------------------------------------------------------------
 +
 +
kernel.sysrq = 1
 +
 +
# -------------------------------------------------------------------------
 +
# General semaphore rules:
 +
# -----------------------
 +
# 1. Semaphore tunable parameters are limited to semmsl, semmns,
 +
#    semopm and semmni and must be entered in the /etc/sysctl.conf
 +
#    file with the following syntax.
 +
#
 +
#    kernel.sem = semmsl semmns semopm semmni
 +
#
 +
# 2. The tunable kernel resource of semmsl sets the maximum number
 +
#    of semaphore per set. The semopm should be set equal to semmsl
 +
#    so that an operation can be performed on every semaphore in
 +
#    the set. If semopm is larger than semmsl it should raise an
 +
#    OS exception but doesn't in Linux.
 +
#
 +
#    Oracle8i Installation Manual for UNIX recommends this value be
 +
#    derived as "... the sum of the PROCESSES parameter for each
 +
#    Oracle database except the largest one, plus 2 times the largest
 +
#    PROCESSES value, plus 10 times the number of Oracle databases."
 +
#    Assuming 2 Oracle8i databases with the init{SID}.ora "processes"
 +
#    parameter set to 100 and 1 Oracle 9iAS server with "processes"
 +
#    parameter set to 100, the following is the recommended value:
 +
#
 +
#    Variables:
 +
#    =========
 +
#    s = sum of processes for all but largest instance
 +
#    m = maximum number of process for a single instance
 +
#    n = total number of instances
 +
#    i = n - largest instance.
 +
#
 +
#    semmsl = ((s * i) + (m * 2)) + (n * 10))
 +
#
 +
#    semmsl = ((100*2) + (100)*2) + (3 * 10)) = (400 + 30) = 430
 +
#
 +
#    semopm = semmsl = 430
 +
#
 +
# 3. The tunable kernel resource of semmni sets the system wide
 +
#    semaphore sets by creating a semid_ds control structure of
 +
#    84 bytes, so this parameter should not be set arbitrarily large.
 +
#    The Oracle8i and Oracle9i installation manual recommends 100
 +
#    for each Oracle instance. Assuming 2 Oracle8i databases with
 +
#    the init{SID}.ora processes parameter set to 100 and 1 Oracle
 +
#    9iAS server with processes parameter set to 100, the following
 +
#    is the recommended value:
 +
#
 +
#    semmni = 300
 +
#
 +
# 4. The semmsl (maximum number of semaphores per identifier) value
 +
#    is the product of the semmni and semmsl values, as qualified
 +
#    below:
 +
#
 +
#    semmns = (semmni * semmsl) = 300 * 430 = 129000
 +
#
 +
# 5. Therefore, semaphores should be set in the /etc/sysctl.conf
 +
#    file as follows:
 +
# -------------------------------------------------------------------------
 +
 +
kernel.sem = 430 129000 430 300
 +
 +
# -------------------------------------------------------------------------
 +
# General semaphore rules:
 +
# -----------------------
 +
# 1. The "Oracle9i Installation Guide, Release 2 (9.2.0.1.0) for
 +
#    UNIX Systems: AIX-Based Systems, Compaq Tru64 UNIX, HP 9000
 +
#    Series HP-UX, Linux Intel, and Sun Solaris" manual (A96167)
 +
#    advises default settings for shmmin, shmmni, shmseg and
 +
#    shmvmx shared memory kernel values.
 +
#
 +
# 2. The shmmin should be set to 1.
 +
#
 +
# 3. The shmmni memory variable sets the maximum number of
 +
#    system wide shmid_ds structures and should be equal to the
 +
#    value determined for semmni value.
 +
#
 +
#    shmmni = semmni = 300
 +
#
 +
# 4. The shmmax should be set to 50% of available memory or 2 GB but
 +
#    setting above 50% of available memory can cause some memory use
 +
#    issues in Oracle8i.
 +
#
 +
# 5. The shmmin, shmmsg and shmvmx cannot be set when using the
 +
#    Red Hat Advanced Server 2.1 because alteration of the kernel is
 +
#    not supported by Oracle and these typically tunable parameters
 +
#    are fixed in the supported and shipped kernels.
 +
#
 +
# -------------------------------------------------------------------------
 +
 +
kernel.shmmni = 300
 +
kernel.shmmax = 2147483648
 +
 +
# -------------------------------------------------------------------------
 +
# General File Management:
 +
# -----------------------
 +
# The default value of 8192 is not compatible with Oracle's file limit
 +
# of 65536 and should be changed to that value or higher provided memory
 +
# is available. For example, the typical rule-of-thumb is to divide real
 +
# memory by 16,384, or 64 simultaneous open files per 1 MB of memory.
 +
# In systems with large amounts of memory, concurrency of file access
 +
# would be a better rule-of-thumb. The value is set based on 2 GB of
 +
# real memory as follows below.
 +
#
 +
#    fs.file-max = ( 2,097,152,000 / 16384 ) = 128,000
 +
#
 +
# Using the 2.2.x Linux kernel you will need to set the inode-max
 +
# value to 4 to 5 times the file-max value. However, beginning with the
 +
# 2.4.x Linux kernel inode-max is managed dynamically and should not be
 +
# set in the /etc/sysctl.conf file.
 +
# -------------------------------------------------------------------------
 +
 +
fs.file-max=128000
  
−
        Validate kernel boot parameters.
 
  
−
        The following command enables validation of kernel parameters that are set in the /etc/sysctl.conf file that are processed at boot time.
+
Reboot agar perubahan parameter berefek.
  
−
        # sysctl -p | grep kernel
+
Validasi kernel boot parameter. Setelah booting, cek menggunakan perintah berikut,
 +
 +
sysctl -p | grep kernel
  
−
        kernel.sysrq = 0
+
Hasilnya
−
        kernel.core_uses_pid = 1
 
−
        kernel.sem = 430 129000 430 300
 
−
        kernel.shmmni = 300
 
−
        kernel.shmmax = 2147483648
 
  
 +
kernel.sysrq = 0
 +
kernel.core_uses_pid = 1
 +
kernel.sem = 430 129000 430 300
 +
kernel.shmmni = 300
 +
kernel.shmmax = 2147483648
  
 
==Benchmark==
 
==Benchmark==
  
 +
* Lmbench http://www.bitmover.com/lmbench/get_lmbench.html
 +
 +
===Kadaluarsa===
 +
 +
* Kernbench http://freecode.com/projects/kernbench
 
* Tbench
 
* Tbench
 
* Dbench
 
* Dbench
 
* SPECJbb
 
* SPECJbb
−
* Lmbench
 
−
* Kernbench http://freecode.com/projects/kernbench
 
 
* Hackbench
 
* Hackbench
  
 
==Referensi==
 
==Referensi==
  
 +
* http://archive09.linux.com/feature/146599
 +
* http://linux.die.net/man/8/sysctl
 
* http://www.techtinker.com/linux/LinuxKernel.html#HowRedHat
 
* http://www.techtinker.com/linux/LinuxKernel.html#HowRedHat
 
* https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Performance_Tuning_Guide/index.html - '''BAGUS'''
 
* https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Performance_Tuning_Guide/index.html - '''BAGUS'''
Line 209: Line 299:
  
 
==Pranala Menarik==
 
==Pranala Menarik==
 +
 +
* [[Linux]]
 +
* [[Ubuntu]]
 +
* [[Buku Sistem Operasi]]
 +
 +
===Secara Umum===
 +
 +
* [[Sistem Operasi]]
 +
 +
===Instalasi Linux===
 +
 +
* [[Linux: CLI untuk Survival]]
 +
* [[Linux: Skema Partisi di Linux]]
 +
* [[Linux: Instalasi Sistem Operasi]]
 +
* [[Membuat Repository Ubuntu Lokal menggunakan debmirror]]
 +
 +
===Compile Kernel===
 +
 +
* [[Kernel]]
 +
* [[OS: Linux Kernel]]
 +
* [[Kernel: Anatomi Kernel Source]]
 +
* [[Compile Kernel]]
 +
* [[Compile Kernel: Konfigurasi Kernel]]
 +
 +
===Remaster Linux===
 +
 +
* [[Cara Cepat Melakukan Remastering Ubuntu]]
 +
 +
===Sistem Operasi untuk Embedded===
 +
 +
* [[OpenWRT]]
 +
* [[OpenWRT: Download Firmware yang sudah jadi]]
 +
* [[OpenWRT: Source Repository Download]]
 +
* [[OpenWRT: Melihat Daftar Package]]
 +
 +
====Membuat Firmware Sendiri====
 +
 +
* [[OpenWRT: Build Firmware]]
 +
* [[OpenWRT: Build Firmware Buffalo WZRHPG450H]]
 +
* [[OpenWRT: Build Firmware Buffalo WZRHPG300N]]
 +
* [[OpenWRT: Build Firmware Ubiquiti NanoStation2]]
 +
* [[OpenWRT: Build Firmware Mikrotik RB433]]
 +
* [[OpenWRT: Build Firmware Linksys WRT160NL]]
 +
* [[OpenWRT: Build Firmware Linksys WRT54GL]]
 +
 +
====Flash ke Device====
 +
 +
* [[OpenWRT: Flash Linksys WRT54GL]]
 +
* [[OpenWRT: Flash Buffalo WZRHP450H]]
 +
* [[OpenWRT: Flash Buffalo WZRHP300N]]
 +
* [[OpenWRT: Flash UBNT NanoStation2]]
 +
* [[OpenWRT: Flash Linksys WRT160NL]]
 +
 +
====Beberapa Tip====
 +
 +
* [[OpenWRT: Mikrotik RB433]]
 +
* [[OpenWRT: 3G modem]]
 +
* [[OpenWRT: Build Firmware dengan 3G Modem Support]]
 +
* [[OpenWRT: Setup Firewall]]
 +
* [[OpenWRT: Konfigurasi UBNT NanoStation2 tanpa WebGUI]]
 +
 +
===Tuning Kernel===
 +
 +
* [[OS: Parameter Kernel Default]]
 +
 +
====Tuning Kernel Scheduler====
 +
 +
* [[OS: Kernel Scheduler]]
 +
* [[OS: Tuning Kernel Scheduler]]
 +
* [[OS: Tuning Completely Fair scheduler CFS]]
 +
* [[OS: Complete Teori Tuning Kernel Scheduler]]
 +
 +
====Tuning I/O Scheduler====
 +
 +
* [[OS: Tuning Completely Fair Queueing CFQ I/O scheduler]]
 +
* [[OS: Complete Teori Tuning I/O Performance]]
 +
 +
====Tuning Manajemen Memory====
 +
 +
* [[OS: Tuning Manajemen Memory]]
 +
 +
===Android===
 +
 +
* [[OS: Android - Download]]
 +
 +
===Membuat Kernel Module===
 +
 +
* [[OS: Mengerti System Call]]
 +
* [[OS: Membuat Kernel Modul]]
 +
 +
===Monitoring & Benchmark===
  
 
* [[OS: Build in Monitoring Tool]]
 
* [[OS: Build in Monitoring Tool]]
 +
* [[Linux Benchmarking]]
 +
* [[OS: Benchmarking menggunakan UnixBench]]
 +
* [[OS: Benchmarking menggunakan LLCBench]]

Latest revision as of 05:42, 9 May 2013

Mengapa tune kernel?

Perilaku default kernel UNIX biasanya tidak optimal karena sulit untuk mengantisipasi jenis pekerjaan atau beban kerja yang akan diberikan kepada sistem operasi . Oleh karena itu, UNIX menyediakan parameter yang dapat mengubah alokasi sumber daya. Parameter kernel tuning adalah spesifik UNIX.

Administrator sistem bertanggung jawab untuk menentukan jenis target pekerjaan dan beban kerja untuk mesin dan untuk memantau apakah terjadi perubahan dari waktu ke waktu. Administrator sistem harus memastikan bahwa setiap parameter kernel diatur untuk mengoptimalkan kinerja mesin.

CATATAN: Tuning Kernel merupakan topik lanjut dan tidak boleh dilakukan tanpa pemahaman lengkap tentang hal tersebut.

Kernel tuning with sysctl

Sumber: http://archive09.linux.com/feature/146599 Oleh Federico Kereki 9 September 2008 (4:00:00 PM)

Kernel Linux cukup fleksibel, kita bahkan dapat memodifikasi cara kerjanya sambil komputer jalan secara dinamis mengubah beberapa parameter, berkat perintah sysctl. Sysctl menyediakan sebuah antarmuka yang memungkinkan kita untuk memeriksa dan mengubah ratusan parameter kernel di Linux atau BSD. Perubahan segera berlaku, dan bahkan ada cara untuk membuat parameter tersebut tidak hilang setelah reboot. Dengan menggunakan sysctl secara bijak, kita dapat mengoptimalkan komputer tanpa harus mengkompilasi ulang kernel , dan mendapatkan hasilnya dengan cepat.

Untuk mendapatkan sedikit rasa parameter apa saja yang dapat di modifikasi oleh sysctl, jalankan sysctl -a 

$ sysctl -a

Hasilnya 

kernel.sched_child_runs_first = 0
kernel.sched_min_granularity_ns = 1500000
kernel.sched_latency_ns = 12000000
kernel.sched_wakeup_granularity_ns = 2000000
kernel.sched_tunable_scaling = 1
kernel.sched_migration_cost = 500000
kernel.sched_nr_migrate = 32
kernel.sched_time_avg = 1000
kernel.sched_shares_window = 10000000
kernel.timer_migration = 1
kernel.sched_rt_period_us = 1000000
kernel.sched_rt_runtime_us = 950000
kernel.sched_autogroup_enabled = 1
kernel.sched_cfs_bandwidth_slice_us = 5000
kernel.panic = 0
... dan seterusnya ...

Jika kita ingin mendapatkan nilai hanya satu variabel, gunakan perintah seperti 

sysctl vm.swappiness

atau hanya 

sysctl vm

untuk daftar semua variabel yang dimulai dengan "vm." Tambahkan opsi -n untuk mengeluarkan hanya nilai variabel, tanpa nama,-N memiliki efek sebaliknya, dan menghasilkan nama-nama tapi tidak nilai.

Kita dapat mengubah nlai variabel dengan menggunakan opsi-w dengan sintaks 

sysctl -w variable=nilai

Misalnya, 

sysctl -w net.ipv6.conf.all.forwarding=1

set variabel menjadi benar / true (0 sama dengan "tidak" atau "salah", 1 berarti "ya" atau "benar") sehingga memungkinkan IP6 forwarding. Anda mungkin tidak membutuhkan opsi -w tampaknya akan usang.

Informasi lebih lanjut tentang sysctl dapat di baca dengan cara mengetik 

man sysctl


sysctl dan directory /proc

Virtual directory /proc/sys juga memberikan interface ke parameter sysctl memungkinkan kita untuk melihat dan mengubah parameter tersebut. Contoh, file /proc/sys/vm/swappiness sama dengan parameter vm.swappiness parameter di sysctl.conf. Oleh karenanya, melakukan 

echo 10 >/proc/sys/vm/swappiness

sama dengan 

sysctl -w vm.swappiness=10

Yang perlu kita perhatikan, jika file /proc/sys read-only, maka kita tidak akan bisa mengubahnya juga dengan sysctl.

Tulis 

ls /proc/sys/kernel

untuk melihat parameter kernel yang bisa kita ubah.

sysctl.conf

Nilai paramter sysctl akan di load dari file /etc/sysctl.conf saat boot. File ini dapat memiliki baris kosong, komen (start dengan #), dan baris dengan format "variable=nilai" format. Contoh isi sysctl.conf adalah sebagai berikut, 

# Disable response to broadcasts.
net.ipv4.icmp_echo_ignore_broadcasts = 1

# enable route verification on all interfaces
net.ipv4.conf.all.rp_filter = 1

# enable ipV6 forwarding
net.ipv6.conf.all.forwarding = 1

# increase the number of possible inotify(7) watches
fs.inotify.max_user_watches = 65536

Jika kita ingin mengaktifkan / mereload parameter sysctl, dapat dilakukan dengan perintah 

sysctl -p.


Sumber: http://www.techtinker.com/linux/LinuxKernel.html#HowRedHat


Contoh Tuning Kernel untuk Oracle9i

Contoh berikut adalah tuning Linux Kernel sebelum menginstalasi Oracle9i atau Oracle Applications 11i.

Edit file /etc/sysctl.conf 

vi /etc/sysctl.conf

Contoh konfigurasi 

# -------------------------------------------------------------------------
# Kernel parameter assumptions and rationale.
# ===========================================

# -------------------------------------------------------------------------
# Disables packet forwarding
# -------------------------------------------------------------------------

net.ipv4.ip_forward = 0

# -------------------------------------------------------------------------
# Enables source route verification
# -------------------------------------------------------------------------

net.ipv4.conf.default.rp_filter = 1

# -------------------------------------------------------------------------
# Set the default local port range.
# -------------------------------------------------------------------------

net.ipv4.ip_local_port_range = 1024 65000

# -------------------------------------------------------------------------
# Enables the magic-sysrq key
# -------------------------------------------------------------------------

kernel.sysrq = 1

# -------------------------------------------------------------------------
# General semaphore rules:
# -----------------------
# 1. Semaphore tunable parameters are limited to semmsl, semmns,
#    semopm and semmni and must be entered in the /etc/sysctl.conf
#    file with the following syntax.
#
#    kernel.sem = semmsl semmns semopm semmni
#
# 2. The tunable kernel resource of semmsl sets the maximum number
#    of semaphore per set. The semopm should be set equal to semmsl
#    so that an operation can be performed on every semaphore in
#    the set. If semopm is larger than semmsl it should raise an
#    OS exception but doesn't in Linux.
#
#    Oracle8i Installation Manual for UNIX recommends this value be
#    derived as "... the sum of the PROCESSES parameter for each
#    Oracle database except the largest one, plus 2 times the largest
#    PROCESSES value, plus 10 times the number of Oracle databases."
#    Assuming 2 Oracle8i databases with the init{SID}.ora "processes"
#    parameter set to 100 and 1 Oracle 9iAS server with "processes"
#    parameter set to 100, the following is the recommended value:
#
#    Variables:
#    =========
#    s = sum of processes for all but largest instance
#    m = maximum number of process for a single instance
#    n = total number of instances
#    i = n - largest instance.
#
#    semmsl = ((s * i) + (m * 2)) + (n * 10))
#
#    semmsl = ((100*2) + (100)*2) + (3 * 10)) = (400 + 30) = 430
#
#    semopm = semmsl = 430
#
# 3. The tunable kernel resource of semmni sets the system wide
#    semaphore sets by creating a semid_ds control structure of
#    84 bytes, so this parameter should not be set arbitrarily large.
#    The Oracle8i and Oracle9i installation manual recommends 100
#    for each Oracle instance. Assuming 2 Oracle8i databases with
#    the init{SID}.ora processes parameter set to 100 and 1 Oracle
#    9iAS server with processes parameter set to 100, the following
#    is the recommended value:
#
#    semmni = 300
#
# 4. The semmsl (maximum number of semaphores per identifier) value
#    is the product of the semmni and semmsl values, as qualified
#    below:
#
#    semmns = (semmni * semmsl) = 300 * 430 = 129000
#
# 5. Therefore, semaphores should be set in the /etc/sysctl.conf
#    file as follows:
# -------------------------------------------------------------------------

kernel.sem = 430 129000 430 300

# -------------------------------------------------------------------------
# General semaphore rules:
# -----------------------
# 1. The "Oracle9i Installation Guide, Release 2 (9.2.0.1.0) for
#    UNIX Systems: AIX-Based Systems, Compaq Tru64 UNIX, HP 9000
#    Series HP-UX, Linux Intel, and Sun Solaris" manual (A96167)
#    advises default settings for shmmin, shmmni, shmseg and
#    shmvmx shared memory kernel values.
#
# 2. The shmmin should be set to 1.
#
# 3. The shmmni memory variable sets the maximum number of
#    system wide shmid_ds structures and should be equal to the
#    value determined for semmni value.
#
#    shmmni = semmni = 300
#
# 4. The shmmax should be set to 50% of available memory or 2 GB but
#    setting above 50% of available memory can cause some memory use
#    issues in Oracle8i.
#
# 5. The shmmin, shmmsg and shmvmx cannot be set when using the
#    Red Hat Advanced Server 2.1 because alteration of the kernel is
#    not supported by Oracle and these typically tunable parameters
#    are fixed in the supported and shipped kernels.
#
# -------------------------------------------------------------------------

kernel.shmmni = 300
kernel.shmmax = 2147483648

# -------------------------------------------------------------------------
# General File Management:
# -----------------------
# The default value of 8192 is not compatible with Oracle's file limit
# of 65536 and should be changed to that value or higher provided memory
# is available. For example, the typical rule-of-thumb is to divide real
# memory by 16,384, or 64 simultaneous open files per 1 MB of memory.
# In systems with large amounts of memory, concurrency of file access
# would be a better rule-of-thumb. The value is set based on 2 GB of
# real memory as follows below.
#
#    fs.file-max = ( 2,097,152,000 / 16384 ) = 128,000
#
# Using the 2.2.x Linux kernel you will need to set the inode-max
# value to 4 to 5 times the file-max value. However, beginning with the
# 2.4.x Linux kernel inode-max is managed dynamically and should not be
# set in the /etc/sysctl.conf file.
# -------------------------------------------------------------------------

fs.file-max=128000


Reboot agar perubahan parameter berefek.

Validasi kernel boot parameter. Setelah booting, cek menggunakan perintah berikut, 

sysctl -p | grep kernel

Hasilnya 

kernel.sysrq = 0
kernel.core_uses_pid = 1
kernel.sem = 430 129000 430 300
kernel.shmmni = 300
kernel.shmmax = 2147483648

Benchmark

Kadaluarsa

Referensi

I/O Scheduler

Pranala Menarik

Secara Umum

Instalasi Linux

Compile Kernel

Remaster Linux

Sistem Operasi untuk Embedded

Membuat Firmware Sendiri

Flash ke Device

Beberapa Tip

Tuning Kernel

Tuning Kernel Scheduler

Tuning I/O Scheduler

Tuning Manajemen Memory

Android

Membuat Kernel Module

Monitoring & Benchmark

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