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1–30 of 874

Welcome to the Mechanical Sympathy group. This group is for discussing how to code sympathetically for the underlying stack/platform so good performance can be extracted.

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Steven Stewart-Gallus, Richard Startin5

1/28/19

Do modern JVMs use aliasing information?

Ahah! I believe I might have a possible hacky workaround! Instead of doing: static void mul(int[]

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Do modern JVMs use aliasing information?

Ahah! I believe I might have a possible hacky workaround! Instead of doing: static void mul(int[]

1/28/19

Ross Black, … nigr...@gmail.com12

4/28/19

Long time to safepoint

Sorry to join late the party, but...a read only mmap isn't equally dangerous? If the page cache

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Long time to safepoint

Sorry to join late the party, but...a read only mmap isn't equally dangerous? If the page cache

4/28/19

yang liu, … Nitsan Wakart4

9/28/17

jvm stuck in SafepointSynchronize::begin()

Thanks Alex! For future reference to all here: AFAIK lightweight-java-profiler has never progressed

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jvm stuck in SafepointSynchronize::begin()

Thanks Alex! For future reference to all here: AFAIK lightweight-java-profiler has never progressed

9/28/17

Nathan Fisher, … Shripad Agashe8

9/25/17

Measuring latency of a function call

Thanks for the link to Alekseys video. I'll give it a viewing! On Mon, 25 Sep 2017 at 06:10,

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Measuring latency of a function call

Thanks for the link to Alekseys video. I'll give it a viewing! On Mon, 25 Sep 2017 at 06:10,

9/25/17

yang liu, … Gil Tene6

9/19/17

ConcurrentHashMap size() method could read stale value?

My dive into the specifics (of eg the volatile load) probably confused the issue. Nothing on either

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ConcurrentHashMap size() method could read stale value?

My dive into the specifics (of eg the volatile load) probably confused the issue. Nothing on either

9/19/17

Dain Ironfoot, … Martin Thompson7

9/22/17

Lock and Little's Law

Can the critical path itself change based on concurrent load if each of the paths making up the graph

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feedback-requested

Lock and Little's Law

Can the critical path itself change based on concurrent load if each of the paths making up the graph

9/22/17

dan.m...@gmail.com2

9/12/17

Stuck data in disruptor

apologiez, please, remove this post, I forgot that it should be asked on Disruptor forum On Tuesday,

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Stuck data in disruptor

apologiez, please, remove this post, I forgot that it should be asked on Disruptor forum On Tuesday,

9/12/17

Vero K., … Ben Evans11

4/16/17

Socket buffer and rates streaming

This is the same architecture employed by >1 IB for their in-house solution. It's a pretty

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Socket buffer and rates streaming

This is the same architecture employed by >1 IB for their in-house solution. It's a pretty

4/16/17

Chris Newland, … Nitsan Wakart6

2/10/17

HotSpot code cache and instruction prefetching

We have no availability based heuristics, nor does anyone else AFAIK, for dynamically enabling/

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HotSpot code cache and instruction prefetching

We have no availability based heuristics, nor does anyone else AFAIK, for dynamically enabling/

2/10/17

Дмитрий Пеньков, … Alex Bagehot9

1/29/17

you are trying to give 200 JVMs 10 core each. Before separating all 200 JVMs "see" all 80

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you are trying to give 200 JVMs 10 core each. Before separating all 200 JVMs "see" all 80

1/29/17

Ivan Kelly, … Vitaly Davidovich17

12/14/16

Minimum realistic GC time for G1 collector on 10GB

Have you tried just setting -Xmx10g and -XX:MaxGCPauseMillis=10? This is typically a good baseline to

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Minimum realistic GC time for G1 collector on 10GB

Have you tried just setting -Xmx10g and -XX:MaxGCPauseMillis=10? This is typically a good baseline to

12/14/16

Alexey Pirogov, … Steve Gury8

12/12/16

Profiling using hardware counters on Mac OS X

If you're ok with disabling macOS kernel security (loading only signed kernel module), you can

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Profiling using hardware counters on Mac OS X

If you're ok with disabling macOS kernel security (loading only signed kernel module), you can

12/12/16

11/4/16

Java 8 loop optimization puzzle

Hi all, I faced a puzzling performance behavior that seems to be link to the asm generated, I wrote a

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Java 8 loop optimization puzzle

Hi all, I faced a puzzling performance behavior that seems to be link to the asm generated, I wrote a

11/4/16

Wayne, … Martin Thompson12

3/9/17

Question about SBE and DirectBuffer

If you can it would be best to raise an issue on the GitHub repo with a repeatable test. This looks

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Question about SBE and DirectBuffer

If you can it would be best to raise an issue on the GitHub repo with a repeatable test. This looks

3/9/17

Miron Aseev, Avi Kivity3

9/18/16

Batching strategies in Netty

Yeah, I think you're right. I'm going to create a topic on the Netty mailing list. Thanks. On

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Batching strategies in Netty

Yeah, I think you're right. I'm going to create a topic on the Netty mailing list. Thanks. On

9/18/16

Sumit Srivastava, ymo2

2/25/16

Time bounded code section, without threads

Assuming you have multiple computing threads and one collector thread. All you need is : 1) a

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Time bounded code section, without threads

Assuming you have multiple computing threads and one collector thread. All you need is : 1) a

2/25/16

11/10/15

Java GARBAGE_COLLECTION_NOTIFICATION Received for NOT A REAL GC with every information being ZERO

Hope anyone can enlighten me about a special garbage collection notification with all the data

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Java GARBAGE_COLLECTION_NOTIFICATION Received for NOT A REAL GC with every information being ZERO

Hope anyone can enlighten me about a special garbage collection notification with all the data

11/10/15

lior simon, … Jacob Hansson22

5/19/15

Java - Reuse String Instances

We did a spike on this a few years ago, playing with trying to get a netty stack allocation free.

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Java - Reuse String Instances

We did a spike on this a few years ago, playing with trying to get a netty stack allocation free.

5/19/15

Jean Dagenais, … Jean-Philippe BEMPEL23

1/6/17

Systematic Process to Reduce Linux OS Jitter

Hi, Those servers seem nice, but there is a huge no-go for us and our workload: There is only one

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Systematic Process to Reduce Linux OS Jitter

Hi, Those servers seem nice, but there is a huge no-go for us and our workload: There is only one

1/6/17

Alex Zhitnitsky

12/11/14

Website feedback

Hi everyone, This might be a bit off-topic, we're working on a new homepage and would love to

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feedback-requested

Website feedback

Hi everyone, This might be a bit off-topic, we're working on a new homepage and would love to

12/11/14

Dain Ironfoot, Georges Gomes2

11/19/14

Assembling MPSC using SPSC queues

Hi Disclaimer: Measurements are always preferred. But here are my thoughts: If you create your

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feedback-requested

Assembling MPSC using SPSC queues

Hi Disclaimer: Measurements are always preferred. But here are my thoughts: If you create your

11/19/14

Elazar Leibovich, … Aleksey Shipilev8

5/7/14

Help find problems with my LongAdder benchmark

What Martin said. If you want to learn more about benchmarking, try to digest this first: http://hg.

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Help find problems with my LongAdder benchmark

What Martin said. If you want to learn more about benchmarking, try to digest this first: http://hg.

5/7/14

Denis Orlov, … Rüdiger Möller7

4/10/14

Detecting cause of java app freezing

Just as a blind shot: I have had similar issues caused by stream redirection to an external python

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ResponseTimeMeasurement

Detecting cause of java app freezing

Just as a blind shot: I have had similar issues caused by stream redirection to an external python

4/10/14

Nathan Tippy, … Peter Lawrey8

3/20/14

Supporting mixed sequence of Ints and longs in Java/Android

Afaik android doesn't have intrinsics for ByteBuffer / Unsafe. This should impact performance. On

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Supporting mixed sequence of Ints and longs in Java/Android

Afaik android doesn't have intrinsics for ByteBuffer / Unsafe. This should impact performance. On

3/20/14

Gleb Smirnov, … Nitsan Wakart34

7/27/15

JMH vs Caliper: reference thread

JMH has one type of load which is "All-out", it is very deterministically all out. You can

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JMH vs Caliper: reference thread

JMH has one type of load which is "All-out", it is very deterministically all out. You can

7/27/15

Attila-Mihaly Balazs

1/27/14

Survey on sun.misc.Unsafe

From Doug Lea (http://cs.oswego.edu/pipermail/concurrency-interest/2014-January/012274.html): Hi, We

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Survey on sun.misc.Unsafe

From Doug Lea (http://cs.oswego.edu/pipermail/concurrency-interest/2014-January/012274.html): Hi, We

1/27/14

Rüdiger Möller, … Jean-Philippe BEMPEL12

11/10/13

Wierd Performance Difference between int and long ...

Thanx for your clarification Jean, I am impressed :-) Am Donnerstag, 7. November 2013 21:18:24 UTC+1

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Wierd Performance Difference between int and long ...

Thanx for your clarification Jean, I am impressed :-) Am Donnerstag, 7. November 2013 21:18:24 UTC+1

11/10/13

u935903.brown.edu, … Martin Thompson12

10/24/13

conceptual tradeoffs re: use of taskset(1) to permute/pin 8xJVM grid's w CPU affinity

I know you are not recommending such practice :-) I know you well enough to know better. I just want

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conceptual tradeoffs re: use of taskset(1) to permute/pin 8xJVM grid's w CPU affinity

I know you are not recommending such practice :-) I know you well enough to know better. I just want

10/24/13

Eugene Morozov, … Martin Grajcar12

10/15/13

Forward vs backward loop over array performance

Some more specifics regarding the original forward vs backward. My colleague bind my loops to the

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PrintCompilation

Forward vs backward loop over array performance

Some more specifics regarding the original forward vs backward. My colleague bind my loops to the

10/15/13

Eugene Morozov, … Rüdiger Möller15

10/9/13

[Wrappers vs Primitives] memory footprints measurements

I totally agree, but nobody in their mind will allow such a changes even on a mid size enterprise

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[Wrappers vs Primitives] memory footprints measurements

I totally agree, but nobody in their mind will allow such a changes even on a mid size enterprise

10/9/13

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