Re: [sqlmap-users] CPU utilization
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From: Kasper F. <th...@ma...> - 2010-03-15 13:48:08
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Hi I am no expert at all in Python. It was just my impression as a programmer that there is some kind of busy-waiting. Without knowing anything, I just threw in "Can this really be true?". Is there really no other way to implement fetching pages then using busy-waiting. Actually I just wanted to know if this could be implemented, so my hardware was not abused. But from what you tell me, it seems that urllib2 is fetching pages using busy-waiting and this is a module that cannot be changed. I checked the file you mentioned but I can't really read the code very well. /Kasper On 15-03-2010 14:26, Miroslav Stampar wrote: > Hi. > > That's because, when you do the urllib2 page request, current thread > goes into blocking state - no events here, just plain raw CPU power. > If you do it with 30 threads for example, all of them go into blocking > state. I repeat, python's standard module Urllib2 doesn't support > asynchronous page retrievals (neither any other). > > Could you please be so kind and review > sqlmap/lib/techniques/blind/inference.py, methods bisection(...) and > getChar(...), and advise with some concrete solution. We'll be more > than happy to hear from you. > > Kind regards. > > On Mon, Mar 15, 2010 at 1:58 PM, Kasper Føns<th...@ma...> wrote: > >> Hi >> >> I still don't get why sqlmap is using that much cpu then? >> >> On 15-03-2010 13:49, Miroslav Stampar wrote: >> >>> Hi Kasper. >>> >>> Threads are indeed in a blocking state while retrieving page content >>> (basic socket blocking). Basic python urllib2 doesn't support >>> asynchronous page retrievals, but we could put this on a feature >>> request list (http://eventlet.net/doc/, >>> http://twistedmatrix.com/trac/). >>> >>> Kind regards. >>> >>> On Mon, Mar 15, 2010 at 1:24 PM, Kasper Føns<th...@ma...> wrote: >>> >>> >>>> Dead Miroslav >>>> >>>> That was not the point I was trying to make. It would ofcourse be nice to >>>> utilize the 100% of my computer when a program wants to, but I can see >>>> that >>>> python is crippled in the matter. But what I was asking about was: >>>> I think it is strange that sqlmap uses 50% of my cpu - What operations >>>> could >>>> require that much cpu? It seems that if a connection to a target is slow, >>>> sqlmap still uses 50% of the cpu. Is it besy-waiting for the thread that >>>> is >>>> doing the I/O operation to complete? >>>> >>>> I'll try again: >>>> I would see sqlmap's main bottlenet as the internet connection. I can't >>>> find >>>> anything to justify to use my CPU as much as it does. Therefore I think >>>> some >>>> thread is besy-waiting, which really cripples the system (especially if I >>>> only had 1 CPU). So my question is, is it busy-waiting? >>>> >>>> PS: Thanks for the nice link. Was interesting reading. >>>> >>>> /Kasper >>>> >>>> On 15-03-2010 13:17, Miroslav Stampar wrote: >>>> >>>> >>>>> Dear Kasper. >>>>> >>>>> Python has an "technical" issue dealing with multithreading programs. >>>>> In part that it can't run threads on multiple cores, it has a really >>>>> nasty "GIL" problem which is discussed here: >>>>> http://www.snaplogic.com/blog/?p=94. Threading of sqlmap really speeds >>>>> it up, but the side effect is that CPU-throttling you are talking >>>>> about, especially in a high number of threads used. >>>>> >>>>> Kind regards. >>>>> >>>>> On Mon, Mar 15, 2010 at 12:55 PM, Kasper Føns<th...@ma...> wrote: >>>>> >>>>> >>>>> >>>>>> Hello sqlmap users. >>>>>> >>>>>> I have a question about how sqlmap utilizes the cpu. On my computer the >>>>>> CPU being utilized is nearly always 50%, and since I have two cores I >>>>>> suspect some thread to be in deadlock or maybe doing busy-waiting. >>>>>> If using busy-waiting, I would suggest using an event-based approach >>>>>> instead. >>>>>> >>>>>> /Kasper >>>>>> >>>>>> >>>>>> >>>>>> ------------------------------------------------------------------------------ >>>>>> Download Intel® Parallel Studio Eval >>>>>> Try the new software tools for yourself. Speed compiling, find bugs >>>>>> proactively, and fine-tune applications for parallel performance. >>>>>> See why Intel Parallel Studio got high marks during beta. >>>>>> http://p.sf.net/sfu/intel-sw-dev >>>>>> _______________________________________________ >>>>>> sqlmap-users mailing list >>>>>> sql...@li... >>>>>> https://lists.sourceforge.net/lists/listinfo/sqlmap-users >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>>> >>>> >>>> >>> >>> >>> >> >> > > > |