The only way to avoid garbagge collection is to pre-allocate all the objects used by your app. You may have to use pools of objects or tricks like that to make sure you don't create objects while the augmented reality portion is running. This is no different from an action game. There are some open source games out there that do a good job at this, for example, Replica Island.
On Jun 7, 2:53 am, Jay Ha <[email protected]> wrote: > Hi. > > I'm writing an Augmented Reallity codes that should works in realtime, > > But the VM's garbage collection hinders my program's performance. > > I checked my program's execution time for each in OnPrevFrame(byte[], > Camera) > > and it execution time increases from around 50ms to 120ms at just > after each garbage collection. > > I copied parts of logs below. > (local time is just before and after of signal processing, and global > time is time stamps for every onPreviewFrame() calling ) > ----------------------------------------------------------------------------------------------------------------------------------------- > 06-06 18:42:26.340: WARN/matchTarget(725): global 151844ms, local > 167ms > 06-06 18:42:26.390: WARN/matchTarget(725): global 55ms, local 54ms > 06-06 18:42:26.510: DEBUG/dalvikvm(725): GC_FOR_MALLOC freed 20 > objects / 346432 bytes in 88ms > 06-06 18:42:26.510: WARN/matchTarget(725): global 119ms, local > 115ms > 06-06 18:42:26.600: WARN/matchTarget(725): global 83ms, local 75ms > 06-06 18:42:26.670: WARN/matchTarget(725): global 76ms, local 70ms > 06-06 18:42:26.740: WARN/matchTarget(725): global 66ms, local 63ms > 06-06 18:42:26.820: DEBUG/dalvikvm(725): GC_FOR_MALLOC freed 73 > objects / 464096 bytes in 55ms > 06-06 18:42:26.830: WARN/matchTarget(725): global 95ms, local 94ms > 06-06 18:42:26.890: WARN/matchTarget(725): global 57ms, local 56ms > 06-06 18:42:26.940: WARN/matchTarget(725): global 46ms, local 45ms > 06-06 18:42:27.000: WARN/matchTarget(725): global 59ms, local 59ms > 06-06 18:42:27.070: DEBUG/dalvikvm(725): GC_FOR_MALLOC freed 144 > objects / 466776 bytes in 56ms > 06-06 18:42:27.080: WARN/matchTarget(725): global 80ms, local 79ms > 06-06 18:42:27.150: WARN/matchTarget(725): global 71ms, local 65ms > 06-06 18:42:27.210: WARN/matchTarget(725): global 61ms, local 60ms > 06-06 18:42:27.250: WARN/matchTarget(725): global 41ms, local 39ms > 06-06 18:42:27.310: WARN/matchTarget(725): global 57ms, local 41ms > 06-06 18:42:27.350: DEBUG/dalvikvm(725): GC_FOR_MALLOC freed 207 > objects / 584128 bytes in 39ms > 06-06 18:42:27.420: WARN/matchTarget(725): global 116ms, local > 59ms > 06-06 18:42:27.470: WARN/matchTarget(725): global 50ms, local 49ms > 06-06 18:42:27.530: WARN/matchTarget(725): global 58ms, local 55ms > 06-06 18:42:27.620: DEBUG/dalvikvm(725): GC_FOR_MALLOC freed 210 > objects / 353680 bytes in 58ms > 06-06 18:42:27.630: WARN/matchTarget(725): global 96ms, local 95ms > 06-06 18:42:27.690: WARN/matchTarget(725): global 61ms, local 57ms > 06-06 18:42:27.740: WARN/matchTarget(725): global 57ms, local 55ms > 06-06 18:42:27.820: WARN/matchTarget(725): global 76ms, local 68ms > 06-06 18:42:27.870: WARN/matchTarget(725): global 49ms, local 46ms > 06-06 18:42:27.900: DEBUG/dalvikvm(725): GC_FOR_MALLOC freed 226 > objects / 469944 bytes in 34ms > 06-06 18:42:27.970: WARN/matchTarget(725): global 97ms, local 55ms > 06-06 18:42:28.000: WARN/matchTarget(725): global 39ms, local 38ms > 06-06 18:42:28.080: WARN/matchTarget(725): global 80ms, local 61ms > 06-06 18:42:28.170: DEBUG/dalvikvm(725): GC_FOR_MALLOC freed 220 > objects / 469184 bytes in 50ms > 06-06 18:42:28.170: WARN/matchTarget(725): global 86ms, local 84ms > 06-06 18:42:28.230: WARN/matchTarget(725): global 60ms, local 52ms > 06-06 18:42:28.280: WARN/matchTarget(725): global 52ms, local 51ms > 06-06 18:42:28.340: WARN/matchTarget(725): global 61ms, local 59ms > 06-06 18:42:28.420: DEBUG/dalvikvm(725): GC_FOR_MALLOC freed 193 > objects / 468200 bytes in 53ms > 06-06 18:42:28.430: WARN/matchTarget(725): global 82ms, local 81ms > 06-06 18:42:28.490: WARN/matchTarget(725): global 64ms, local 57ms > 06-06 18:42:28.550: WARN/matchTarget(725): global 61ms, local 60ms > 06-06 18:42:28.610: WARN/matchTarget(725): global 57ms, local 56ms > 06-06 18:42:28.690: DEBUG/dalvikvm(725): GC_FOR_MALLOC freed 205 > objects / 468832 bytes in 58ms > 06-06 18:42:28.700: WARN/matchTarget(725): global 88ms, local 86ms > 06-06 18:42:28.750: WARN/matchTarget(725): global 58ms, local 55ms > 06-06 18:42:28.810: WARN/matchTarget(725): global 54ms, local 53ms > 06-06 18:42:28.860: WARN/matchTarget(725): global 52ms, local 51ms > 06-06 18:42:28.990: DEBUG/dalvikvm(725): GC_FOR_MALLOC freed 226 > objects / 469544 bytes in 42ms > 06-06 18:42:28.990: WARN/matchTarget(725): global 134ms, local > 100ms > 06-06 18:42:29.060: WARN/matchTarget(725): global 62ms, local 52ms > 06-06 18:42:29.100: WARN/matchTarget(725): global 49ms, local 47ms > 06-06 18:42:29.160: WARN/matchTarget(725): global 51ms, local 50ms > 06-06 18:42:29.240: DEBUG/dalvikvm(725): GC_FOR_MALLOC freed 197 > objects / 468320 bytes in 52ms > 06-06 18:42:29.240: WARN/matchTarget(725): global 84ms, local 83ms > 06-06 18:42:29.290: WARN/matchTarget(725): global 51ms, local 43ms > 06-06 18:42:29.350: WARN/matchTarget(725): global 53ms, local 39ms > 06-06 18:42:29.410: WARN/matchTarget(725): global 69ms, local 44ms > 06-06 18:42:29.470: WARN/matchTarget(725): global 54ms, local 44ms > ----------------------------------------------------------------------------------------------------------------------------------------- > > Also I executed onPreviewFrame without any signal processing on it, > but > > the garbage collection is also carried showing debegging message > around 60ms it spends for memory release. > > Is this garbage collection come from releasing byte[] yuvs image data? > ( i uses 320x240 thumb nail ) > > then... this clealy comes from Java's limitation, so there will be no > hope for improvement unless > > I found a way to directly access camera device? do you think this is > feasible? > > Hope listen to others' comments. -- You received this message because you are subscribed to the Google Groups "Android Developers" group. 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