On Wed, Jan 21, 2015 at 3:51 PM, Christopher Schultz < ch...@christopherschultz.net> wrote:
> -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA256 > > Daniel, > > On 1/21/15 3:16 PM, Daniel Mikusa wrote: > > On Wed, Jan 21, 2015 at 2:59 PM, Mike Seda > > <mike.s...@lillegroup.com> wrote: > > > >> Is it advisable to have the following JVM option set in Tomcat 7 > >> (with Java 7)? -XX:+DisableExplicitGC > >> > > > > It may or may not make a difference. Some questions like these > > come to mind... > > > > - How would you feel if one of the applications you deployed > > called System.gc()? - How about if it called it a lot? or at a > > really inconvenient time? - How much do you trust your apps or > > their developers? - Does one of your apps rely on that > > functionality for some reason? > > Our application does not call System.gc automatically, but we have > that ability through an admin screen where we can say "do GC now", and > we call it. Sometimes when we have a heap that's been high for a while > - -- say, tripping our monitoring software a lot -- we go in there and > hit the GC button to see what happens. Usually, heap usage goes down > to 25% of what it had been before... it's just that the JVM hadn't > done a full GC in a while because it didn't need to. > I've done that too, but initiated the GC through jvisualvm. I was wondering if DisableExplicitGC would prevent that as well, so I did a quick test and it seemed to prevent it. Guess that's something to consider too. Dan > > >> Or will this prevent Tomcat itself from calling System.gc() when > >> it needs to? > > > > I really doubt Tomcat would call that. > > Tomcat calls System.gc() in only one place -- > StandardHost.findReloadedContextMemoryLeaks -- which is mostly a > debugging tool. > > - -chris > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1 > Comment: GPGTools - http://gpgtools.org > > iQIcBAEBCAAGBQJUwBFtAAoJEBzwKT+lPKRYiVMP/RAaAjPpKJWio+0I2Zrwnvu1 > xryvw4Ua7DiVzh9ZVFy2NWvw92ReSUWxw6Uf2sKUVOwuC0X5HhnKh7VKtS1fy3h0 > 6zt/o3StQfugEx/lPA7L1uREJOedM1GOHcKeHNKhC3JQUVH2VKELraO+TMYkCiDU > iiMr7pxoPC/TvCYFKQNgVom5TSEcYi18RL//UU/gBZPk+2ZHV8DbyW0wbLG65Lu2 > FDEZw01tEqrRpIZrRndECL+9NbGEv6vLte1bPEk+2pImcaIKYME+z20ztsa8KfA1 > kbQO6yLvhW4tREH/3SZqfacway4qOxjKQFWqDmkosm7HJXXKlEqsDT+Mi19mTD26 > QvD8aQ6tCp5m6SPG89MN5dk6zHtnjVXrjaVMVx75e0IwSN35aJcUm3g5fTdXLwR6 > vB4U3T958jt5/uD/k9QxJVB15R8+YdU29iBdxKKQ2C86eGa6jUdizaexNPPnaGPi > R9xrSpHo9JjR/5uC1fIcSgwC6JfVH+j8y5j5Yx87vDllD70IkIgh6wtqxdBmL5as > 7poC/h8D3TmZwKVtXoAf+DaFIZye9tqxyD8x56XLjVLfBSt9eta0ppunPtqY61KT > feHBshR7IXvkP29h2rHnP0Yo5abFgQgz8+jFJSmhKpX9CuKtscToCE9Wbgf5ejST > HZSKRwOUMcCVomv4hTwq > =WE8p > -----END PGP SIGNATURE----- > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > >
