diff options
Diffstat (limited to 'src/runtime/select.go')
| -rw-r--r-- | src/runtime/select.go | 118 |
1 files changed, 32 insertions, 86 deletions
diff --git a/src/runtime/select.go b/src/runtime/select.go index 8b6c3ed4c0..508a19b630 100644 --- a/src/runtime/select.go +++ b/src/runtime/select.go @@ -304,7 +304,7 @@ func selectgoImpl(sel *hselect) (uintptr, uint16) { k *scase sglist *sudog sgnext *sudog - futile byte + qp unsafe.Pointer ) loop: @@ -317,15 +317,12 @@ loop: switch cas.kind { case caseRecv: - if c.dataqsiz > 0 { - if c.qcount > 0 { - goto asyncrecv - } - } else { - sg = c.sendq.dequeue() - if sg != nil { - goto syncrecv - } + sg = c.sendq.dequeue() + if sg != nil { + goto recv + } + if c.qcount > 0 { + goto bufrecv } if c.closed != 0 { goto rclose @@ -338,15 +335,12 @@ loop: if c.closed != 0 { goto sclose } - if c.dataqsiz > 0 { - if c.qcount < c.dataqsiz { - goto asyncsend - } - } else { - sg = c.recvq.dequeue() - if sg != nil { - goto syncsend - } + sg = c.recvq.dequeue() + if sg != nil { + goto send + } + if c.qcount < c.dataqsiz { + goto bufsend } case caseDefault: @@ -363,6 +357,9 @@ loop: // pass 2 - enqueue on all chans gp = getg() done = 0 + if gp.waiting != nil { + throw("gp.waiting != nil") + } for i := 0; i < int(sel.ncase); i++ { cas = &scases[pollorder[i]] c = cas.c @@ -389,7 +386,7 @@ loop: // wait for someone to wake us up gp.param = nil - gopark(selparkcommit, unsafe.Pointer(sel), "select", traceEvGoBlockSelect|futile, 2) + gopark(selparkcommit, unsafe.Pointer(sel), "select", traceEvGoBlockSelect, 2) // someone woke us up sellock(sel) @@ -432,16 +429,13 @@ loop: } if cas == nil { - futile = traceFutileWakeup + // This can happen if we were woken up by a close(). + // TODO: figure that out explicitly so we don't need this loop. goto loop } c = cas.c - if c.dataqsiz > 0 { - throw("selectgo: shouldn't happen") - } - if debugSelect { print("wait-return: sel=", sel, " c=", c, " cas=", cas, " kind=", cas.kind, "\n") } @@ -470,7 +464,7 @@ loop: selunlock(sel) goto retc -asyncrecv: +bufrecv: // can receive from buffer if raceenabled { if cas.elem != nil { @@ -485,29 +479,20 @@ asyncrecv: if cas.receivedp != nil { *cas.receivedp = true } + qp = chanbuf(c, c.recvx) if cas.elem != nil { - typedmemmove(c.elemtype, cas.elem, chanbuf(c, c.recvx)) + typedmemmove(c.elemtype, cas.elem, qp) } - memclr(chanbuf(c, c.recvx), uintptr(c.elemsize)) + memclr(qp, uintptr(c.elemsize)) c.recvx++ if c.recvx == c.dataqsiz { c.recvx = 0 } c.qcount-- - sg = c.sendq.dequeue() - if sg != nil { - gp = sg.g - selunlock(sel) - if sg.releasetime != 0 { - sg.releasetime = cputicks() - } - goready(gp, 3) - } else { - selunlock(sel) - } + selunlock(sel) goto retc -asyncsend: +bufsend: // can send to buffer if raceenabled { raceacquire(chanbuf(c, c.sendx)) @@ -523,47 +508,18 @@ asyncsend: c.sendx = 0 } c.qcount++ - sg = c.recvq.dequeue() - if sg != nil { - gp = sg.g - selunlock(sel) - if sg.releasetime != 0 { - sg.releasetime = cputicks() - } - goready(gp, 3) - } else { - selunlock(sel) - } + selunlock(sel) goto retc -syncrecv: +recv: // can receive from sleeping sender (sg) - if raceenabled { - if cas.elem != nil { - raceWriteObjectPC(c.elemtype, cas.elem, cas.pc, chanrecvpc) - } - racesync(c, sg) - } - if msanenabled && cas.elem != nil { - msanwrite(cas.elem, c.elemtype.size) - } - selunlock(sel) + recv(c, sg, cas.elem, func() { selunlock(sel) }) if debugSelect { print("syncrecv: sel=", sel, " c=", c, "\n") } if cas.receivedp != nil { *cas.receivedp = true } - if cas.elem != nil { - typedmemmove(c.elemtype, cas.elem, sg.elem) - } - sg.elem = nil - gp = sg.g - gp.param = unsafe.Pointer(sg) - if sg.releasetime != 0 { - sg.releasetime = cputicks() - } - goready(gp, 3) goto retc rclose: @@ -580,29 +536,19 @@ rclose: } goto retc -syncsend: - // can send to sleeping receiver (sg) +send: + // can send to a sleeping receiver (sg) if raceenabled { raceReadObjectPC(c.elemtype, cas.elem, cas.pc, chansendpc) - racesync(c, sg) } if msanenabled { msanread(cas.elem, c.elemtype.size) } - selunlock(sel) + send(c, sg, cas.elem, func() { selunlock(sel) }) if debugSelect { print("syncsend: sel=", sel, " c=", c, "\n") } - if sg.elem != nil { - syncsend(c, sg, cas.elem) - } - sg.elem = nil - gp = sg.g - gp.param = unsafe.Pointer(sg) - if sg.releasetime != 0 { - sg.releasetime = cputicks() - } - goready(gp, 3) + goto retc retc: if cas.releasetime > 0 { |