Loadrunner中多线程与多进程的区别
上一篇 / 下一篇 2011-12-14 14:51:46 / 个人分类:LoadRunner
用户可以在Controller的run-time setting中选择Vuser的运行方式:多进程/多线程。
~0RY6P)uso051Testing软件测试网@,c}I/c:?;t多进程和多线程方式的区别是:
$c8r&rIz3Gm0,uE(j W[C0Controller将使用驱动程序mdrv运行Vuser。如果按进程方式运行每个Vuser,则对于每个Vuser实例,都将启动一个mdrv进程。多个mdrv进程会占用大量内存及其他系统资源,这就限制了可以在任一负载生成器上运行的Vuser的数量。如果选择按线程方式运行,在默认情况下,Controller为每50个Vuser仅启动一个mdrv.exe进程,而每个Vuser都按线程运行,这些线程Vuser将共享父进程的内存段。这就节省了大量内存控件,从而可以在一个负载生成器上运行更多的Vuser。
JV0Rj;h&[Uoa0'qiblQq0但是任何选择都是有两面性的。选择线程方式运行Vuser会带来一些安全问题。因为线程的资源是从进程资源中分配出来的,因此同一个进程中的多个线程会有共享的内存空间,这样可能会引起多个线程的同步问题,调度不好,就会出问题,不如A线程要用的资源就必须等待B线程释放,而B也在等待其他资源释放才能继续。这就会出现这样的问题:同一个测试场景,用线程并发就会超时失败或报错,而用进程并发就没错。
F%TFW%JGS0A;e"Me9Z0一个组里10个用户和10个组每个组一个用户有什么区别?
y*?l;_8a0 我们先看一下LR的官方帮助:
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zd*m"u"a d9H`wMW,W0Multithreading51Testing软件测试网,K`xM!G$Q~;]
Vusers support multithread environments. The primary advantage of a multithread environment is the ability to run more Vusers per load generator. Only threadsafe protocols should be run as threads. (not applicable to Mercury Business Availability Center)51Testing软件测试网(XK8k"]+P/viXY)}$kw
Note: The following protocols are not threadsafe: Sybase-Ctlib, Sybase-Dblib, Informix, Tuxedo, and PeopleSoft-Tuxedo.51Testing软件测试网iNL9t*J
o To enable multithreading, click Run Vuser as a thread.
1GTR(dY|f/x0o To disable multithreading and run each Vuser as a separate process, click Run Vuser as a process.51Testing软件测试网9A$\Z;dSG
The Controller and Tuning Console use a driver program (such as mdrv.exe or r3vuser.exe) to run your Vusers. If you run each Vuser as a process, then the same driver program is launched (and loaded) into the memory again and again for every instance of the Vuser. Loading the same driver program into memory uses up large amounts of RAM (random access memory) and other system resources. This limits the numbers of Vusers that can be run on any load generator.51Testing软件测试网*|3E}5C#}-t
Alternatively, if you run each Vuser as a thread, the Controller or Tuning Console launches only one instance of the driver program (such as mdrv.exe), for every 50 Vusers (by default). This driver process/program launches several Vusers, each Vuser running as a thread. These threaded Vusers share segments of the memory of the parent driver process. This eliminates the need for multiple re-loading of the driver program/process saves much memory space, thereby enabling more Vusers to be run on a single load generator.
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从上面的描述可以看到,
AR!HJs0 如果是线程安全的协议,在一个组(进程)里并发多个vusers,可以不用开那么进程。这可以减少系统的开销。51Testing软件测试网"Q-E$PwK
如果不是线程安全的协议,我们需要开多个进程来处理Vusers。这样势必增加系统的开销。51Testing软件测试网 ^dYAi7@2k
其实对现在的硬件来说,基本上客户端成为瓶颈的机会不是很大。(除非这公司太穷了)
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:?t%|Pb&kZ0 这里我做了个实验,画了一张表,来形象的说明一下组/vusers/线程/进程的关系。
i-^`B {D h)@:a0注:这里,我假定的是10vsuers:51Testing软件测试网&X