How to change compilation policy to trigger C2 compilation ASAP?

[Zoltán Majó]

Hi Wei,


On 05/20/2015 10:07 AM, Tangwei (Euler) wrote:
> Hi Zoltan,
>    Is this option supported in OpenJDK8? I cannot find it by greping output of command line 'java -XX:+PrintFlagsFinal'.

I checked and it is available only in 9.

Best regards,


Zoltan

>
>
> Regards!
> wei
>
>> -----Original Message-----
>> From: hotspot-compiler-dev
>> [mailto:hotspot-compiler-dev-bounces at openjdk.java.net] On Behalf Of Zoltán
>> Majó
>> Sent: Wednesday, May 20, 2015 2:47 PM
>> To: hotspot-compiler-dev at openjdk.java.net
>> Subject: Re: How to change compilation policy to trigger C2 compilation ASAP?
>>
>> Hi Wei,
>>
>>
>> On 05/20/2015 03:12 AM, Vladimir Kozlov wrote:
>> [...]
>>> An other approach is to set threshold per method (scale all
>>> threasholds (C1, C2, interpreter) by this value). For example to
>>> reduce thresholds by half:
>>>
>>>
>> -XX:CompileCommand=option,SomeClass.someMethod,double,CompileThresh
>> old
>>> Scaling,0.5
>>>
>> just to complement what Vladimir suggested: If you want to scale thresholds
>> for all methods at once, the CompileThresholdScaling can be also used globally.
>> For example, -XX:CompileThresholdScaling=0.5 would reduce all thresholds by
>> half (both with tiered and non-tiered modes of operation).
>>
>> Best regards,
>>
>>
>> Zoltan
>>
>>> Vladimir
>>>
>>> On 5/19/15 5:43 PM, Tangwei (Euler) wrote:
>>>> My goal is just to reach peak performance quickly. Following is one
>>>> tier threshold combination I tried:
>>>>
>>>> -XX:Tier0ProfilingStartPercentage=0
>>>>
>>>> -XX:Tier3InvocationThreshold=3
>>>>
>>>> -XX:Tier3MinInvocationThreshold=2
>>>>
>>>> -XX:Tier3CompileThreshold=2
>>>>
>>>> -XX:Tier4InvocationThreshold=4
>>>>
>>>> -XX:Tier4MinInvocationThreshold=3
>>>>
>>>> -XX:Tier4CompileThreshold=2
>>>>
>>>> Regards!
>>>>
>>>> wei
>>>>
>>>> *From:*Vitaly Davidovich [mailto:vitalyd at gmail.com]
>>>> *Sent:* Tuesday, May 19, 2015 9:33 PM
>>>> *To:* Tangwei (Euler)
>>>> *Cc:* hotspot compiler
>>>> *Subject:* Re: How to change compilation policy to trigger C2
>>>> compilation ASAP?
>>>>
>>>> Is your goal specifically to have C2 compile or just to reach peak
>>>> performance quickly? It sounds like the latter.  What values did you
>>>> specify for the tier thresholds? Also, it may help you to
>>>> -XX:+PrintCompilation to tune the flags as this will show you which
>>>> methods are being compiled, when, and at what tier.
>>>>
>>>> sent from my phone
>>>>
>>>> On May 19, 2015 9:01 AM, "Tangwei (Euler)" <tangwei6 at huawei.com
>>>> <mailto:tangwei6 at huawei.com>> wrote:
>>>>
>>>> Hi All,
>>>>
>>>>     I want to run a JAVA application on a performance simulator, and
>>>> do a profiling on a hot function JITTed with C2 compiler.
>>>>
>>>> In order to make C2 compiler compile hot function as early as
>>>> possible, I hope to reduce the threshold of function invocation
>>>>
>>>> count in interpreter and C1 to drive the JIT compiler transitioned to
>>>> Level 4 (C2) ASAP. Following is the option list I try, but
>>>>
>>>> failed to find a right combination to meet my requirement. Anyone can
>>>> help to figure out what options I can use?
>>>>
>>>> Thanks in advance.
>>>>
>>>> -XX:Tier0ProfilingStartPercentage=0
>>>>
>>>> -XX:Tier3InvocationThreshold
>>>>
>>>> -XX:Tier3MinInvocationThreshold
>>>>
>>>> -XX:Tier3CompileThreshold
>>>>
>>>> -XX:Tier4InvocationThreshold
>>>>
>>>> -XX:CompileThreshold
>>>>
>>>> -XX:Tier4MinInvocationThreshold
>>>>
>>>> -XX:Tier4CompileThreshold
>>>>
>>>> Regards!
>>>>
>>>> wei
>>>>