trim -o trim-frames-and-calls-trim.trace --frames=5/frame --calls=2 glxsimple.trace
dump --verbose trim-frames-and-calls-trim.trace
0 glXMakeCurrent(dpy = 0x236a280, drawable = 41943041, ctx = 0x2384330) = True
1 glXSwapBuffers(dpy = 0x236a280, drawable = 41943041)