3176 // space per-gc-thread buffers. The default is 4kw.
3177 FLAG_SET_CMDLINE(uintx, YoungPLABSize, 256*K); // Note: this is in words
3178
3179 // OldPLABSize is the size of the buffers in the old gen that
3180 // UseParallelGC uses to promote live data that doesn't fit in the
3181 // survivor spaces. At any given time, there's one for each gc thread.
3182 // The default size is 1kw. These buffers are rarely used, since the
3183 // survivor spaces are usually big enough. For specjbb, however, there
3184 // are occasions when there's lots of live data in the young gen
3185 // and we end up promoting some of it. We don't have a definite
3186 // explanation for why bumping OldPLABSize helps, but the theory
3187 // is that a bigger PLAB results in retaining something like the
3188 // original allocation order after promotion, which improves mutator
3189 // locality. A minor effect may be that larger PLABs reduce the
3190 // number of PLAB allocation events during gc. The value of 8kw
3191 // was arrived at by experimenting with specjbb.
3192 FLAG_SET_CMDLINE(uintx, OldPLABSize, 8*K); // Note: this is in words
3193
3194 // Enable parallel GC and adaptive generation sizing
3195 FLAG_SET_CMDLINE(bool, UseParallelGC, true);
3196 FLAG_SET_DEFAULT(ParallelGCThreads,
3197 Abstract_VM_Version::parallel_worker_threads());
3198
3199 // Encourage steady state memory management
3200 FLAG_SET_CMDLINE(uintx, ThresholdTolerance, 100);
3201
3202 // This appears to improve mutator locality
3203 FLAG_SET_CMDLINE(bool, ScavengeBeforeFullGC, false);
3204
3205 // Get around early Solaris scheduling bug
3206 // (affinity vs other jobs on system)
3207 // but disallow DR and offlining (5008695).
3208 FLAG_SET_CMDLINE(bool, BindGCTaskThreadsToCPUs, true);
3209
3210 } else if (match_option(option, "-XX:+NeverTenure", &tail)) {
3211 // The last option must always win.
3212 FLAG_SET_CMDLINE(bool, AlwaysTenure, false);
3213 FLAG_SET_CMDLINE(bool, NeverTenure, true);
3214 } else if (match_option(option, "-XX:+AlwaysTenure", &tail)) {
3215 // The last option must always win.
3216 FLAG_SET_CMDLINE(bool, NeverTenure, false);
3217 FLAG_SET_CMDLINE(bool, AlwaysTenure, true);
|
3176 // space per-gc-thread buffers. The default is 4kw.
3177 FLAG_SET_CMDLINE(uintx, YoungPLABSize, 256*K); // Note: this is in words
3178
3179 // OldPLABSize is the size of the buffers in the old gen that
3180 // UseParallelGC uses to promote live data that doesn't fit in the
3181 // survivor spaces. At any given time, there's one for each gc thread.
3182 // The default size is 1kw. These buffers are rarely used, since the
3183 // survivor spaces are usually big enough. For specjbb, however, there
3184 // are occasions when there's lots of live data in the young gen
3185 // and we end up promoting some of it. We don't have a definite
3186 // explanation for why bumping OldPLABSize helps, but the theory
3187 // is that a bigger PLAB results in retaining something like the
3188 // original allocation order after promotion, which improves mutator
3189 // locality. A minor effect may be that larger PLABs reduce the
3190 // number of PLAB allocation events during gc. The value of 8kw
3191 // was arrived at by experimenting with specjbb.
3192 FLAG_SET_CMDLINE(uintx, OldPLABSize, 8*K); // Note: this is in words
3193
3194 // Enable parallel GC and adaptive generation sizing
3195 FLAG_SET_CMDLINE(bool, UseParallelGC, true);
3196
3197 // Encourage steady state memory management
3198 FLAG_SET_CMDLINE(uintx, ThresholdTolerance, 100);
3199
3200 // This appears to improve mutator locality
3201 FLAG_SET_CMDLINE(bool, ScavengeBeforeFullGC, false);
3202
3203 // Get around early Solaris scheduling bug
3204 // (affinity vs other jobs on system)
3205 // but disallow DR and offlining (5008695).
3206 FLAG_SET_CMDLINE(bool, BindGCTaskThreadsToCPUs, true);
3207
3208 } else if (match_option(option, "-XX:+NeverTenure", &tail)) {
3209 // The last option must always win.
3210 FLAG_SET_CMDLINE(bool, AlwaysTenure, false);
3211 FLAG_SET_CMDLINE(bool, NeverTenure, true);
3212 } else if (match_option(option, "-XX:+AlwaysTenure", &tail)) {
3213 // The last option must always win.
3214 FLAG_SET_CMDLINE(bool, NeverTenure, false);
3215 FLAG_SET_CMDLINE(bool, AlwaysTenure, true);
|