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operating system, the size of the process space is 4g,64-bit system 2^64 (which may actually be less than this value). For a long time, I was very puzzled about this, so that does not lead to multiple processes to visit the conflict, for example, two processes are access to address 0x00000010. In fact, the process space for each process is virtual, which is not the same as the physical address. The two are accessing the same virtual address, but the transition to the physical address is differe

to nginx and into the loop. Cslistener > 58518 [FIN, ACK] PHP-FPM Close response58518 > Cslistener [FIN, ACK] nginx shutdown responseCslistener > 58518 [ACK] PHP-FPM responsehttp/1.1 OK (text/html)57939 > http [ACK] Firefox response buffer.php Test Code: 0;$i--){ echo date('H:i:s').''; echo str_repeat(' ', 1024*4); ob_flush(); flush(); sleep(1);}echo 'Stop.';ob_end_flush(); Also note: Nginx gzip may perform output caching, which will result in the flush () function resulti

If you need to use Python to write Excel files, first download or install XLWT.Pip Install XLWTThe following demos should help developers quickly get started writing Excel files using XLWT:Create workbooks (workbook) and Worksheets (sheet):import xlwtworkbook = xlwt.Workbook() sheet = workbook.add_sheet("Sheet Name") Write cell (cell):sheet.write(0, 0, ‘foobar‘) # row, column, valueApply a style to a cell (bold for example):style = xlwt.easyxf(‘font: bold 1‘)sheet.write(0, 0, ‘foobar‘, style)Set

= 8388608net.core.rmem_max = 16777216net.core.wmem_max = 16777216net.core.netdev_max_backlog = 262144net.core.somaxconn = 262144net.ipv4.tcp_max_orphans = 3276800net.ipv4.tcp_max_syn_backlog = 262144net.ipv4.tcp_timestamps = 0net.ipv4.tcp_synack_retries = 1net.ipv4.tcp_syn_retries = 1net.ipv4.tcp_tw_recycle = 1net.ipv4.tcp_tw_reuse = 1net.ipv4.tcp_mem = 94500000 915000000 927000000net.ipv4.tcp_fin_timeout = 1net.ipv4.tcp_keepalive_time = 30net.ipv4.ip_local_port_range = 1024 65000 The following

small, and the heap when it is large; If you do not know the size of the data (it may take a large amount of memory), it is best to use the heap (because of this insurance); If you need to create an array dynamically, use the heap. 1 //experiment Six: Creating arrays dynamically2 int_tmain (intARGC, _tchar*argv[])3 {4 inti;5scanf"%d", i);6 int*array = (int*)malloc(sizeof(int) *i);7 //...//Here are other things to do with dynamically created arrays8 Free(array);9}The last

extension modules, you can reduce unnecessary memory waste. [[emailprotected] etc]# Pmap $ (pgrep php-cgi |head-1) 6746:/usr/local/php/bin/php-cgi–fpm–fpm-config/usr/local /php/etc/php-fpm.conf0000000000400000 6680K r-x–/usr/local/php/bin/php-cgi0000000000c86000 268K rw-/usr/local/php/ bin/php-cgi0000000000cc9000 56K rw-[anon]0000000005012000 2240K rw-[anon]0000003efd200000 112K r-x–/lib64/ld-2.5.so ..... 00002ac28a7a5000 2048k-–/usr/local/php/lib/php/extensions/no-debug-non-zts-20060613/ xhpro

Request_method $request _method; Fastcgi_param Content_Type $content _type; Fastcgi_param content_length $content _length;}An instance in the cache: HTTP { fastcgi_cache_path/path/to/cache levels=1:2 Keys_zone=name :10m inactive=5m; Server { location/{ fastcgi_pass http://127.0.0.1; fastcgi_cache name; fastcgi_cache_valid 302 1h; fastcgi_cache_valid 301 1d; fastcgi_cache_valid any 1m; Fastcgi_cache _min_uses 1; Fastcgi_cache_use_stale error Timeout Invalid_headerp_500;}}} After 0.7.48, the

yuan to buy and play games? Myth two: Four-way Titan second full This is a lot of players in the forum is the most typical of the party, Nvidia launched the super flagship Titan series is really strong, but you really need it and is more than two pieces of SLI? Not necessarily. In fact, the problem of game optimization, similar to the multi-core processor situation, support SLI or Crossfire graphics Parallel technology games are numbered, 80% or more use of the scen

]# MV nginx.conf Nginx.conf.bak[email protected] conf]# Vim nginx.confUser Nobody nobody;#定义启动Nginx的用户Worker_processes 2;#定义子进程数目Error_log/usr/local/nginx/logs/nginx_error.log crit;pid/usr/local/nginx/logs/nginx.pid;Worker_rlimit_nofile 51200;#指定Nginx最多可打开的文件数目Events{Use epoll;Worker_connections 6000;#进程最大连接数}http{Include mime.types;Default_type application/octet-stream;Server_names_hash_bucket_size 3526;Server_names_hash_max_size 4096;Log_format combined_realip ' $remote _addr $http _x_forwarde

, 1280*720, 1600*900, 1920*1080, the unit is PX[note] The relevant knowledge about pixels.If you have retina retina screens, be aware of the difference between the unit PX and PT. If the screen is a normal screen, then 1px = 1pt, equivalent to unit-independentsuch as the iphone6 screen size is 375pt*667pt,dpr=2, so convert to PX, screen resolution of 750PX*1334PX"HD and 4K"Now mobile devices, smart TV advertising the most two keywords estimated is HD,

if the SendMail service is installed.cenos5.8 is installed by default sendmail,centos6.6 is not sendmail by default.Block related knowledge:1) The disk read data is read by block.2) A file may occupy more than one block and consumes disk I/O once per block read.3) If you want to improve disk IO performance, then try to4) A block can only hold the contents of a single file, regardless of the size inside. If block 4 K, that store 1K of files, the remaining 3K is wasted.5) block is not the bigger

but the maximum compression ratio. Gzip_comp_level 5; #设置系统获取几个单位的缓存用于存储gzip的压缩结果数据流. For example, 4 4k represents 4 times times the original data size in 4k, in 4k, for memory. If not set, the default value is to request memory space of the same size as the original data to store gzip compression results. Gzip_buffers 4 16k; #设置需要压缩的数据格式. Nginx only

, block size is 1k/2k/4k,block over the Convention wasted disk disk space, the advantage is high read performance. Summarize:1. The disk partition format file system will be divided into inode and block two parts2.Inode stores the properties of the file and the valid file entity pointer part, the file name in the upper directory of the block , according to the file name found Inode:3.Inode found the corresponding block,block can have multiple,Inode

a descriptor and indexing one of the descriptor entries.Segment Register: The processor saves the information in the descriptor in the segment register, thus avoiding querying the descriptor table each time the memory is accessed.Linear address: indirectly points to the corresponding physical address by specifying a page table, a page in the page table, and an offset value in the page.Page table: An array of simple 32-bit page indicators. The page table itself is also a page of memory, so it co

execution completes, the child process lock consumes the resources to have the parent process to recycle, this is a process life cycle; 4, Thread concept: Thread is a smaller resource scheduling unit than process resources, so also called lightweight process (LWP) and thread scheduling is more resource-saving system, if using a process, Even if the same process needs to allocate two resources, and the thread is different, it can be used in the same process to achieve the reuse of resources, whi

. Here is a simple example:#include The compiler obtains the executable file: $GCC-G-lpthread-wall-o hack_pthread_create hack_pthread_create.cWe can use the command strace to track the thread creation process: $strace./hack_pthread_createThe output of the relevant part of the interface Pthread_create is as follows:Mmap (NULL, 8392704, prot_read| Prot_write, map_private| map_anonymous| Map_stack,-1, 0) = 0x7f70b6c2f000brk (0) = 0x1fe3000brk (0x2004000)

(indexed allocation). Is there any other idiomatic file system that can be compared? Yes, that's our usual flash drive (flash), the file system used in the flash drive is generally in FAT format. The FAT file system does not exist in this format, so fat has no way to read all blocks of the file from the beginning. Each block number is recorded in the previous block, and he reads a bit like this:We assume that the data in the file is written sequentially to the four block numbers of the 1->7->4-

effect.Author Antirez Several reasons for explaining why to implement the VM himself (6). The main OS VM swap out is based on the page concept, such as OS VM1 page is 4K, 4K as long as there is an element even if only 1 bytes are accessed, the page will not be swap, the same reason, read a byte may be swapped into 4K of useless memory. Redis's own implementation

we can find the following line:It tells us that the size of each inode is 256Byte. Of course, the size of each machine will be different, it is actually in the system to format the disk when the decision.Well, the second question has an answer. The original new empty file will occupy disk space, the actual consumption is 256Byte. Oh, no, the exact argument should be an inode size, and the specific value is determined at the time of formatting. Let's talk about creating a new empty directory. T

, NF represents the forward label, NB for the backward label, n is the value of 1-10 decimal digits(4) "Movb $1,1 (%%edi) \n\t"Mem_map[i]==0 is mem_map[0. PAGING_PAGES-1)] In reverse order the first found equal to 0 of the target,The lowest position of the EDI is 1. That is mem_map[i]=1, the flag is occupied for the page, not the spare bit(5) "Sall $12,%%ecx\n\t"At this time ecx save is mem_map[i] subscript I, that is, the relative number of pages,Example:If Mem_map[0: ( PAGING_PAGES-1)] [last p