Re: luajit state CPU time limit
- From: Theo Schlossnagle <jesus@xxxxxxxxxx>
- To: Александр Киранов <xhaskx@xxxxxxxxx>
- Date: Wed, 5 Nov 2014 14:05:00 +0100
The solution I'd like to see is very similar to what you're implying. I'd
love the luaJIT vm and JITted code to check for a deadman timer ever so
often (configurable or every 100k instructions). Then I could set a timer
that would set the deadman and then the lua coroutine in question would
notice and error out unwinding everything cleanly.
I've not spent enough time looking into the implementation to understand
how hard this would be.
Mike would likely have insight on how difficult this would be or if it is
wrought with peril and is a bad approach.
Best regards,
Theo
On Wed, Nov 5, 2014 at 1:59 PM, Александр Киранов <xhaskx@xxxxxxxxx> wrote:
> Thanks, Theo, I realized that there is nothing to do with already running
> JITed code.
>
> Other question: can I change luajit С source somewhere to force it to
> produce JITed code with some custom function call every Nth operations? (N
> = 1000, 1 000 000 or similar)
> Or to check some pre-defined bool variable before each Nth operation?
>
>
> ---
> С уважением,
> Киранов Александр
>
> 2014-11-05 14:53 GMT+03:00 Theo Schlossnagle <jesus@xxxxxxxxxx>:
>
>> The real challenge here is that if you "mess up" and get in an infinited
>> JITted loop, there's nothing to be done about it.
>>
>> I think the only way to do this is by using setitimer() w/ ITIMER_PROF to
>> interrupt the thread and deal with it within the signal handler. The bad
>> part about this is that I haven't figured out how to get LuaJIT to unwind
>> and cleanup cleanly.
>>
>> On Wed, Nov 5, 2014 at 12:47 PM, Александр Киранов <xhaskx@xxxxxxxxx>
>> wrote:
>>
>>> Thanks everybody for proposals.
>>>
>>> Seems I found a solution - call lua_sethook() from different thread, if
>>> I decided to terminate script execution (measured big CPU time consumption).
>>> It's working in usual lua implementation.
>>> But it's not working in luajit - hook is not called immediately after
>>> lua_sethook() call in other thread, only at script end.
>>> Example: http://pastebin.com/HdnfVQKB
>>>
>>> Main question is: is there other way to interrupt lua_State from other
>>> thread? Consistency of interrupted lua_State is not necessary but
>>> preferred, I only need return from luaL_dostring() in main thread with
>>> non-zero result.
>>>
>>>
>>>
>>>
>>> ---
>>> С уважением,
>>> Киранов Александр
>>>
>>> 2014-11-05 14:02 GMT+03:00 Victor Bombi <sonoro@xxxxxxxxxxxxxx>:
>>>
>>>> May be using luaLanes and lane priorities?
>>>> I have not tested in linux but only on win32
>>>>
>>>> ----- Original Message -----
>>>> *From:* Alexander Altshuler <altexy@xxxxxxxxx>
>>>> *To:* luajit@xxxxxxxxxxxxx
>>>> *Sent:* Wednesday, November 05, 2014 10:54 AM
>>>> *Subject:* Re: luajit state CPU time limit
>>>>
>>>> On 4 November 2014 22:47, Javier Guerra Giraldez <javier@xxxxxxxxxxx>
>>>> wrote:
>>>>
>>>>> On Tue, Nov 4, 2014 at 2:34 PM, Александр Киранов <xhaskx@xxxxxxxxx>
>>>>> wrote:
>>>>> > So, when some lua_State consumed too many CPU I need to know it and
>>>>> handle
>>>>> > it on LUA or on C level.
>>>>>
>>>>>
>>>>> better handle it at the OS level. Linux includes many different tools
>>>>> to limit resources. LXC and cgroups spring to mind. I would start
>>>>> here: https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt
>>>>>
>>>>>
>>>> But you will have to decompose your application into some processes to
>>>> get proper control granularity.
>>>>
>>>> Regards
>>>> Alexander
>>>>
>>>>
>>>
>>
>>
>> --
>>
>> Theo Schlossnagle
>>
>> http://omniti.com/is/theo-schlossnagle
>>
>
>
--
Theo Schlossnagle
http://omniti.com/is/theo-schlossnagle
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