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<body class='hmmessage'><div dir='ltr'><span style="color: rgb(68, 68, 68); font-size: 15px; line-height: 21.299999237060547px; background-color: rgb(255, 255, 255);">Hi all,</span><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><br></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);">As you know, sometimes, although compressed-oops are used, if java heap size < 4Gb and it can be moved into low virtual address space (below 4Gb) then compressed oops can be used without encoding/decoding. (<a href="https://wikis.oracle.com/display/HotSpotInternals/CompressedOops" target="_blank" style="line-height: 22.719999313354492px; font-weight: inherit; color: rgb(0, 104, 207); cursor: pointer; font-size: 12pt;">https://wikis.oracle.com/display/HotSpotInternals/CompressedOops</a><span style="line-height: 22.719999313354492px; font-size: 12pt;">)</span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><span style="line-height: 22.719999313354492px; font-size: 12pt;"><br></span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><span style="line-height: 22.719999313354492px; font-size: 12pt;">In 64 bit JVM with compressed-oops enable and and with minimum heap size 1G and maximum heap size 1G, object references are 4 byte. In this case, compressed-oop is real native address.</span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><span style="line-height: 22.719999313354492px; font-size: 12pt;"><br></span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><span style="line-height: 22.719999313354492px; font-size: 12pt;">But i</span><span style="line-height: 22.719999313354492px; font-size: 12pt;">n 64 bit JVM with compressed-oops enable and and with minimum heap size 4G and maximum heap size 8G, object references are 4 byte. But in this case, compressed-oop is needed to be encoded/decoded (by 3 bit shifting) before getting real native address.</span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><span style="line-height: 22.719999313354492px; font-size: 12pt;"><br></span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);">In both of cases, compressed-oop is enable, but how can I detect compressed-oops are used as native address or are they need to be <span style="line-height: 22.719999313354492px; font-size: 12pt;"> </span><span style="line-height: 22.719999313354492px; font-size: 12pt;">encoded/decoded ? If they are encoded/decoded, what is the value of bit shifting ?</span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><span style="line-height: 22.719999313354492px; font-size: 12pt;"><br></span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><span style="line-height: 22.719999313354492px; font-size: 12pt;">Thanks in advance.</span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><span style="line-height: 22.719999313354492px; font-size: 12pt;"><br></span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><span style="line-height: 22.719999313354492px; font-size: 12pt;">--</span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><span style="line-height: 22.719999313354492px; font-size: 12pt;"><br></span></div><div style="line-height: 21.299999237060547px; color: rgb(68, 68, 68); font-size: 15px; background-color: rgb(255, 255, 255);"><span style="line-height: 22.719999313354492px; font-size: 12pt;">Serkan ÖZAL </span></div><div><span style="line-height: 22.719999313354492px; font-size: 12pt;"><br></span></div> </div></body>
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