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<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);">Hi </span><span style="letter-spacing: normal; font-family: "Microsoft Yahei"; font-size: 14px; font-weight: 400; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">Denghui</span><span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);">,</span>
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<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);"><br>
</span></div>
<div style="text-align: left; margin: 0px; background-color: rgb(255, 255, 255);">
<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);">It's been considered it, but we like to see a few real use cases before
adding it.</span></div>
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<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);"><br>
</span></div>
<div style="text-align: left; margin: 0px; background-color: rgb(255, 255, 255);">
<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);">Do you see a use case for JDK events or for user defined events?</span></div>
<div style="text-align: left; margin: 0px; background-color: rgb(255, 255, 255);">
<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);"><br>
</span></div>
<div style="text-align: left; margin: 0px; background-color: rgb(255, 255, 255);">
<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);">If user defined, could you describe the events?</span></div>
<div style="text-align: left; margin: 0px; background-color: rgb(255, 255, 255);">
<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);"><br>
</span></div>
<div style="text-align: left; margin: 0px; background-color: rgb(255, 255, 255);">
<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);">The JFR API allows users to create their own throttling mechanism using
the SettingControl class.</span></div>
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<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);"><br>
</span></div>
<div style="text-align: left; margin: 0px; background-color: rgb(255, 255, 255);">
<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);">We are aware of that exception and I/O events could potentially benefit
from throttling, but not sure the mechanism should work similar to native events. There is also visualization aspects to take into consideration. JMC would need to be updated so it can differentiate between outliers or throttling.</span></div>
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<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);"><br>
</span></div>
<div style="text-align: left; margin: 0px; background-color: rgb(255, 255, 255);">
<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);">Thanks,</span></div>
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<span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; font-weight: 400; color: rgb(0, 0, 0);">Erik</span></div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> hotspot-jfr-dev <hotspot-jfr-dev-retn@openjdk.org> on behalf of Denghui Dong <denghui.ddh@alibaba-inc.com><br>
<b>Sent:</b> Wednesday, November 15, 2023 9:20 AM<br>
<b>To:</b> hotspot-jfr-dev <hotspot-jfr-dev@openjdk.java.net><br>
<b>Subject:</b> RFD: Throttling Support for Java-Level JFR Events</font>
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<div style="clear:both">Hi team,<br>
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<span style="margin:.0px; padding:.0px; border:.0px; outline:.0px">We have observed increased adoption of JFR for information collection within our internal applications and frameworks.</span></div>
<div style="margin:.0px; padding:.0px; border:.0px; outline:.0px; color:#000000; font-family:'Microsoft Yahei'; font-size:14.0px; font-style:normal; font-variant-ligatures:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:.0px; text-transform:none; word-spacing:.0px; white-space:normal; text-decoration-style:initial; text-decoration-color:initial; clear:both">
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<div style="margin:.0px; padding:.0px; border:.0px; outline:.0px; clear:both">However, we've encountered situations where critical events occur frequently, prompting us to explore</div>
<div style="margin:.0px; padding:.0px; border:.0px; outline:.0px; clear:both">the possibility of introducing a throttling mechanism for Java-level events.</div>
<div style="margin:.0px; padding:.0px; border:.0px; outline:.0px; clear:both"><br>
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<div style="margin:.0px; padding:.0px; border:.0px; outline:.0px; clear:both">Currently, my understanding is that throttling is exclusively supported for native event ObjectAllocationSample.</div>
<span style="margin:.0px; padding:.0px; border:.0px; outline:.0px">Should we consider extending this feature to Java-level events?</span></div>
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Thanks,</div>
<div style="margin:.0px; padding:.0px; border:.0px; outline:.0px; color:#000000; font-family:'Microsoft Yahei'; font-size:14.0px; font-style:normal; font-variant-ligatures:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:.0px; text-transform:none; word-spacing:.0px; white-space:normal; text-decoration-style:initial; text-decoration-color:initial; clear:both">
Denghui Dong</div>
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