RFR(s): 8205581: PPC64: RTM: Fix abort on native calls

[Gustavo Romero]

Hi Martin,

Thanks for the quick review!

On 06/25/2018 01:37 PM, Doerr, Martin wrote:
> I wonder why you placed the tabort so late in generate_native_wrapper. I'd put it at the Verified Entry Point.

Actually for no particular reason.

So previously:

2247 [Verified Entry Point]
2248   0x00007fff9c816520: mfcr    r22
2249   0x00007fff9c816524: std     r22,8(r1)
2250   0x00007fff9c816528: mflr    r22
2251   0x00007fff9c81652c: std     r22,16(r1)
2252   0x00007fff9c816530: addis   r11,r1,-2
2253   0x00007fff9c816534: std     r0,0(r11)
2254   0x00007fff9c816538: mr      r21,r1
2255   0x00007fff9c81653c: stdu    r1,-176(r1)
2256   0x00007fff9c816540: std     r3,96(r1)
2257   0x00007fff9c816544: addi    r4,r1,96
2258   0x00007fff9c816548: cmpdi   r3,0
2259   0x00007fff9c81654c: bne-    0x00007fff9c816554
2260   0x00007fff9c816550: li      r4,0
2261   0x00007fff9c816554: addi    r3,r16,824        ; ImmutableOopMap{[96]=Oop }
2262   0x00007fff9c816558: addis   r28,r29,7
2263   0x00007fff9c81655c: addi    r28,r28,25944     ;   {internal_word}
2264   0x00007fff9c816560: tabort. r0 <==
...

Now:

2169 [Verified Entry Point]
2170   0x00007fff78816320: tabort. r0 <==
2171   0x00007fff78816324: mfcr    r22
2172   0x00007fff78816328: std     r22,8(r1)
2173   0x00007fff7881632c: mflr    r22
2174   0x00007fff78816330: std     r22,16(r1)
2175   0x00007fff78816334: addis   r11,r1,-2
2176   0x00007fff78816338: std     r0,0(r11)
2177   0x00007fff7881633c: mr      r21,r1
2178   0x00007fff78816340: stdu    r1,-176(r1)
2179   0x00007fff78816344: std     r3,96(r1)
2180   0x00007fff78816348: addi    r4,r1,96
2181   0x00007fff7881634c: cmpdi   r3,0
2182   0x00007fff78816350: bne-    0x00007fff78816358
2183   0x00007fff78816354: li      r4,0
2184   0x00007fff78816358: addi    r3,r16,824        ; ImmutableOopMap{[96]=Oop }
2185   0x00007fff7881635c: addis   r28,r29,7
2186   0x00007fff78816360: addi    r28,r28,25436     ;   {internal_word}
...

Yep, it's better to abort sooner.

new webrev: http://cr.openjdk.java.net/~gromero/8205581/v2/


Best regards,
Gustavo

> Besides that, it looks good to me.
> 
> Thanks,
> Martin
> 
> 
> -----Original Message-----
> From: Gustavo Romero [mailto:gromero at linux.vnet.ibm.com]
> Sent: Montag, 25. Juni 2018 10:21
> To: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>; Doerr, Martin <martin.doerr at sap.com>; hotspot-compiler-dev at openjdk.java.net
> Cc: ppc-aix-port-dev at openjdk.java.net
> Subject: RFR(s): 8205581: PPC64: RTM: Fix abort on native calls
> 
> Hi,
> 
> Could the following change be reviewed please?
> 
> bug   : https://bugs.openjdk.java.net/browse/JDK-8205581
> webrev: http://cr.openjdk.java.net/~gromero/8205581/v1/
> 
> It forces a transactional state to abort before calling native methods, before
> calling runtime, and on uncommon trap checking, mostly because transaction will
> be aborted soon or latter in either case, similarly to what happens on Intel.
> The abort instruction (tabort) is only emitted if UseRTMLocking is "true" and
> any 'tabort' instruction is treated as a 'nop' instruction if TM state is
> non-transactional.
> 
> It fixes the following tests:
> 
> +Passed: compiler/rtm/print/TestPrintPreciseRTMLockingStatistics.java
> +Passed: compiler/rtm/locking/TestRTMDeoptOnHighAbortRatio.java
> 
> 
> Thank you and best regards,
> Gustavo
>