Re: [go-nuts] I found a very strange code that would cause deadlocks and blocking，why???
If you haven't studied concurrency before, I can't recommend any tutorials. To start to learn about concurrency, I'd first recommend _some_ reading and theoretical background. Concurrency is a complex concept. A "10x" multiplier estimation compared to e.g. structured programming is probably right, definitely not a 2x and probably not a 100x. Don't expect to become _proficient_ in concurrent programming in a couple of hours. Probably you won't be able to download a couple of examples and start tinkering with them successfully. A good start is maybe: https://golang.org/doc/faq#csp Then maybe this: https://en.wikipedia.org/wiki/Communicating_sequential_processes The book is available for free: http://www.usingcsp.com/cspbook.pdf Don't expect to absorb the whole book in a couple of hours, it might take from a couple of weeks to a few month to start to see how much you still don't know. As soon as you get a general understanding of concurrent concepts, you'll most probably find adequate tutorials for yourself. (To add to what Jan asked: for sharing code on golang-nuts please share links to play.golang.org.) On 3/1/19, mountain...@gmail.com wrote: > Is there a recommended tutorial? > > 在 2019年3月1日星期五 UTC+8下午12:21:58，Robert Engels写道： >> >> I think it would be helpful if you learned more about concurrent >> programming. It is 10x harder, even with the simplifications that Go >> offers. If you don’t understand the concepts you are going to struggle. >> Start with some tutorials and work your way up. >> >> On Feb 28, 2019, at 10:14 PM, mount...@gmail.com wrote: >> >> This is the stack information printed when blocking, how to see which G >> blocking program? >> >> SIGABRT: abort >> PC=0x7fff9ceabbf2 m=0 sigcode=0 >> >> goroutine 0 [idle]: >> runtime.pthread_cond_wait(0x1967620, 0x19675e0, 0x7fff) >> /usr/local/go/src/runtime/sys_darwin.go:302 +0x51 >> runtime.semasleep(0x, 0x7fff5fbff670) >> /usr/local/go/src/runtime/os_darwin.go:63 +0x85 >> runtime.notesleep(0x19673e0) >> /usr/local/go/src/runtime/lock_sema.go:167 +0xe3 >> runtime.stoplockedm() >> /usr/local/go/src/runtime/proc.go:2165 +0x8a >> runtime.schedule() >> /usr/local/go/src/runtime/proc.go:2565 +0x2d9 >> runtime.park_m(0xc72480) >> /usr/local/go/src/runtime/proc.go:2676 +0xae >> runtime.mcall(0x105722b) >> /usr/local/go/src/runtime/asm_amd64.s:299 +0x5b >> >> goroutine 1 [semacquire]: >> sync.runtime_Semacquire(0xc27794) >> /usr/local/go/src/runtime/sema.go:56 +0x39 >> sync.(*WaitGroup).Wait(0xc27794) >> /usr/local/go/src/sync/waitgroup.go:130 +0x64 >> cmd/go/internal/work.(*Builder).Do(0xc00023b0e0, 0xc0003ee3c0) >> /usr/local/go/src/cmd/go/internal/work/exec.go:174 +0x38e >> cmd/go/internal/run.runRun(0x195c300, 0xc1e0e0, 0x1, 0x1) >> /usr/local/go/src/cmd/go/internal/run/run.go:137 +0x55b >> main.main() >> /usr/local/go/src/cmd/go/main.go:219 +0x7d4 >> >> goroutine 5 [syscall]: >> os/signal.signal_recv(0x0) >> /usr/local/go/src/runtime/sigqueue.go:139 +0x9f >> os/signal.loop() >> /usr/local/go/src/os/signal/signal_unix.go:23 +0x22 >> created by os/signal.init.0 >> /usr/local/go/src/os/signal/signal_unix.go:29 +0x41 >> >> goroutine 50 [select]: >> cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, >> 0xc0004b0620) >> /usr/local/go/src/cmd/go/internal/work/exec.go:155 +0x12f >> created by cmd/go/internal/work.(*Builder).Do >> /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a >> >> goroutine 51 [select]: >> cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, >> 0xc0004b0620) >> /usr/local/go/src/cmd/go/internal/work/exec.go:155 +0x12f >> created by cmd/go/internal/work.(*Builder).Do >> /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a >> >> goroutine 52 [syscall]: >> syscall.Syscall6(0x7, 0x12006, 0xc50c24, 0x0, 0xc0002f43f0, 0x0, 0x0, >> >> 0xc0002f43f0, 0x0, 0xce2400) >> /usr/local/go/src/syscall/asm_darwin_amd64.s:41 +0x5 >> syscall.wait4(0x12006, 0xc50c24, 0x0, 0xc0002f43f0, 0x90, 0x1566d60, >> 0x14cc401) >> /usr/local/go/src/syscall/zsyscall_darwin_amd64.go:34 +0x7b >> syscall.Wait4(0x12006, 0xc50c74, 0x0, 0xc0002f43f0, 0x0, 0x1, 0x1) >> /usr/local/go/src/syscall/syscall_bsd.go:129 +0x51 >> os.(*Process).wait(0xc0002fd4a0, 0xc34a00, 0xc50cf8, 0x0) >> /usr/local/go/src/os/exec_unix.go:38 +0x7b >> os.(*Process).Wait(0xc0002fd4a0, 0x15b89c8, 0x15b89d0, 0x15b89c0) >> /usr/local/go/src/os/exec.go:125 +0x2b >> os/exec.(*Cmd).Wait(0xc00052da20, 0x0, 0x0) >> /usr/local/go/src/os/exec/exec.go:465 +0x5b >> os/exec.(*Cmd).Run(0xc00052da20, 0x50, 0xcdf7c0) >> /usr/local/go/src/os/exec/exec.go:309 +0x5c >> cmd/go/internal/base.RunStdin(0xcdf7c0, 0x1, 0x1) >> /usr/local/go/src/cmd/go/internal/base/base.go:162 +0x11e >>
Re: [go-nuts] I found a very strange code that would cause deadlocks and blocking，why???
Is there a recommended tutorial? 在 2019年3月1日星期五 UTC+8下午12:21:58，Robert Engels写道： > > I think it would be helpful if you learned more about concurrent > programming. It is 10x harder, even with the simplifications that Go > offers. If you don’t understand the concepts you are going to struggle. > Start with some tutorials and work your way up. > > On Feb 28, 2019, at 10:14 PM, mount...@gmail.com wrote: > > This is the stack information printed when blocking, how to see which G > blocking program? > > SIGABRT: abort > PC=0x7fff9ceabbf2 m=0 sigcode=0 > > goroutine 0 [idle]: > runtime.pthread_cond_wait(0x1967620, 0x19675e0, 0x7fff) > /usr/local/go/src/runtime/sys_darwin.go:302 +0x51 > runtime.semasleep(0x, 0x7fff5fbff670) > /usr/local/go/src/runtime/os_darwin.go:63 +0x85 > runtime.notesleep(0x19673e0) > /usr/local/go/src/runtime/lock_sema.go:167 +0xe3 > runtime.stoplockedm() > /usr/local/go/src/runtime/proc.go:2165 +0x8a > runtime.schedule() > /usr/local/go/src/runtime/proc.go:2565 +0x2d9 > runtime.park_m(0xc72480) > /usr/local/go/src/runtime/proc.go:2676 +0xae > runtime.mcall(0x105722b) > /usr/local/go/src/runtime/asm_amd64.s:299 +0x5b > > goroutine 1 [semacquire]: > sync.runtime_Semacquire(0xc27794) > /usr/local/go/src/runtime/sema.go:56 +0x39 > sync.(*WaitGroup).Wait(0xc27794) > /usr/local/go/src/sync/waitgroup.go:130 +0x64 > cmd/go/internal/work.(*Builder).Do(0xc00023b0e0, 0xc0003ee3c0) > /usr/local/go/src/cmd/go/internal/work/exec.go:174 +0x38e > cmd/go/internal/run.runRun(0x195c300, 0xc1e0e0, 0x1, 0x1) > /usr/local/go/src/cmd/go/internal/run/run.go:137 +0x55b > main.main() > /usr/local/go/src/cmd/go/main.go:219 +0x7d4 > > goroutine 5 [syscall]: > os/signal.signal_recv(0x0) > /usr/local/go/src/runtime/sigqueue.go:139 +0x9f > os/signal.loop() > /usr/local/go/src/os/signal/signal_unix.go:23 +0x22 > created by os/signal.init.0 > /usr/local/go/src/os/signal/signal_unix.go:29 +0x41 > > goroutine 50 [select]: > cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, > 0xc0004b0620) > /usr/local/go/src/cmd/go/internal/work/exec.go:155 +0x12f > created by cmd/go/internal/work.(*Builder).Do > /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a > > goroutine 51 [select]: > cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, > 0xc0004b0620) > /usr/local/go/src/cmd/go/internal/work/exec.go:155 +0x12f > created by cmd/go/internal/work.(*Builder).Do > /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a > > goroutine 52 [syscall]: > syscall.Syscall6(0x7, 0x12006, 0xc50c24, 0x0, 0xc0002f43f0, 0x0, 0x0, > 0xc0002f43f0, 0x0, 0xce2400) > /usr/local/go/src/syscall/asm_darwin_amd64.s:41 +0x5 > syscall.wait4(0x12006, 0xc50c24, 0x0, 0xc0002f43f0, 0x90, 0x1566d60, > 0x14cc401) > /usr/local/go/src/syscall/zsyscall_darwin_amd64.go:34 +0x7b > syscall.Wait4(0x12006, 0xc50c74, 0x0, 0xc0002f43f0, 0x0, 0x1, 0x1) > /usr/local/go/src/syscall/syscall_bsd.go:129 +0x51 > os.(*Process).wait(0xc0002fd4a0, 0xc34a00, 0xc50cf8, 0x0) > /usr/local/go/src/os/exec_unix.go:38 +0x7b > os.(*Process).Wait(0xc0002fd4a0, 0x15b89c8, 0x15b89d0, 0x15b89c0) > /usr/local/go/src/os/exec.go:125 +0x2b > os/exec.(*Cmd).Wait(0xc00052da20, 0x0, 0x0) > /usr/local/go/src/os/exec/exec.go:465 +0x5b > os/exec.(*Cmd).Run(0xc00052da20, 0x50, 0xcdf7c0) > /usr/local/go/src/os/exec/exec.go:309 +0x5c > cmd/go/internal/base.RunStdin(0xcdf7c0, 0x1, 0x1) > /usr/local/go/src/cmd/go/internal/base/base.go:162 +0x11e > cmd/go/internal/run.buildRunProgram(0xc00023b0e0, 0xc0003ee3c0, 0x13999b3, > 0xc00023b150) > /usr/local/go/src/cmd/go/internal/run/run.go:151 +0x26d > cmd/go/internal/work.(*Builder).Do.func1(0xc0003ee3c0) > /usr/local/go/src/cmd/go/internal/work/exec.go:107 +0x72 > cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, > 0xc0004b0620) > /usr/local/go/src/cmd/go/internal/work/exec.go:165 +0xbb > created by cmd/go/internal/work.(*Builder).Do > /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a > > goroutine 53 [select]: > cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, > 0xc0004b0620) > /usr/local/go/src/cmd/go/internal/work/exec.go:155 +0x12f > created by cmd/go/internal/work.(*Builder).Do > /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a > > goroutine 24 [chan receive]: > cmd/go/internal/base.processSignals.func1(0xc86f00) > /usr/local/go/src/cmd/go/internal/base/signal.go:21 +0x34 > created by cmd/go/internal/base.processSignals > /usr/local/go/src/cmd/go/internal/base/signal.go:20 +0x93 > > rax0x104 > rbx0xea00 > rcx0x7fff5fbff488 > rdx0xea00 > rdi0x1967620 > rsi0xea01eb00 > rbp
Re: [go-nuts] I found a very strange code that would cause deadlocks and blocking，why???
I think it would be helpful if you learned more about concurrent programming. It is 10x harder, even with the simplifications that Go offers. If you don’t understand the concepts you are going to struggle. Start with some tutorials and work your way up. > On Feb 28, 2019, at 10:14 PM, mountain...@gmail.com wrote: > > This is the stack information printed when blocking, how to see which G > blocking program? > > SIGABRT: abort > PC=0x7fff9ceabbf2 m=0 sigcode=0 > > goroutine 0 [idle]: > runtime.pthread_cond_wait(0x1967620, 0x19675e0, 0x7fff) > /usr/local/go/src/runtime/sys_darwin.go:302 +0x51 > runtime.semasleep(0x, 0x7fff5fbff670) > /usr/local/go/src/runtime/os_darwin.go:63 +0x85 > runtime.notesleep(0x19673e0) > /usr/local/go/src/runtime/lock_sema.go:167 +0xe3 > runtime.stoplockedm() > /usr/local/go/src/runtime/proc.go:2165 +0x8a > runtime.schedule() > /usr/local/go/src/runtime/proc.go:2565 +0x2d9 > runtime.park_m(0xc72480) > /usr/local/go/src/runtime/proc.go:2676 +0xae > runtime.mcall(0x105722b) > /usr/local/go/src/runtime/asm_amd64.s:299 +0x5b > > goroutine 1 [semacquire]: > sync.runtime_Semacquire(0xc27794) > /usr/local/go/src/runtime/sema.go:56 +0x39 > sync.(*WaitGroup).Wait(0xc27794) > /usr/local/go/src/sync/waitgroup.go:130 +0x64 > cmd/go/internal/work.(*Builder).Do(0xc00023b0e0, 0xc0003ee3c0) > /usr/local/go/src/cmd/go/internal/work/exec.go:174 +0x38e > cmd/go/internal/run.runRun(0x195c300, 0xc1e0e0, 0x1, 0x1) > /usr/local/go/src/cmd/go/internal/run/run.go:137 +0x55b > main.main() > /usr/local/go/src/cmd/go/main.go:219 +0x7d4 > > goroutine 5 [syscall]: > os/signal.signal_recv(0x0) > /usr/local/go/src/runtime/sigqueue.go:139 +0x9f > os/signal.loop() > /usr/local/go/src/os/signal/signal_unix.go:23 +0x22 > created by os/signal.init.0 > /usr/local/go/src/os/signal/signal_unix.go:29 +0x41 > > goroutine 50 [select]: > cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, > 0xc0004b0620) > /usr/local/go/src/cmd/go/internal/work/exec.go:155 +0x12f > created by cmd/go/internal/work.(*Builder).Do > /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a > > goroutine 51 [select]: > cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, > 0xc0004b0620) > /usr/local/go/src/cmd/go/internal/work/exec.go:155 +0x12f > created by cmd/go/internal/work.(*Builder).Do > /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a > > goroutine 52 [syscall]: > syscall.Syscall6(0x7, 0x12006, 0xc50c24, 0x0, 0xc0002f43f0, 0x0, 0x0, > 0xc0002f43f0, 0x0, 0xce2400) > /usr/local/go/src/syscall/asm_darwin_amd64.s:41 +0x5 > syscall.wait4(0x12006, 0xc50c24, 0x0, 0xc0002f43f0, 0x90, 0x1566d60, > 0x14cc401) > /usr/local/go/src/syscall/zsyscall_darwin_amd64.go:34 +0x7b > syscall.Wait4(0x12006, 0xc50c74, 0x0, 0xc0002f43f0, 0x0, 0x1, 0x1) > /usr/local/go/src/syscall/syscall_bsd.go:129 +0x51 > os.(*Process).wait(0xc0002fd4a0, 0xc34a00, 0xc50cf8, 0x0) > /usr/local/go/src/os/exec_unix.go:38 +0x7b > os.(*Process).Wait(0xc0002fd4a0, 0x15b89c8, 0x15b89d0, 0x15b89c0) > /usr/local/go/src/os/exec.go:125 +0x2b > os/exec.(*Cmd).Wait(0xc00052da20, 0x0, 0x0) > /usr/local/go/src/os/exec/exec.go:465 +0x5b > os/exec.(*Cmd).Run(0xc00052da20, 0x50, 0xcdf7c0) > /usr/local/go/src/os/exec/exec.go:309 +0x5c > cmd/go/internal/base.RunStdin(0xcdf7c0, 0x1, 0x1) > /usr/local/go/src/cmd/go/internal/base/base.go:162 +0x11e > cmd/go/internal/run.buildRunProgram(0xc00023b0e0, 0xc0003ee3c0, 0x13999b3, > 0xc00023b150) > /usr/local/go/src/cmd/go/internal/run/run.go:151 +0x26d > cmd/go/internal/work.(*Builder).Do.func1(0xc0003ee3c0) > /usr/local/go/src/cmd/go/internal/work/exec.go:107 +0x72 > cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, > 0xc0004b0620) > /usr/local/go/src/cmd/go/internal/work/exec.go:165 +0xbb > created by cmd/go/internal/work.(*Builder).Do > /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a > > goroutine 53 [select]: > cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, > 0xc0004b0620) > /usr/local/go/src/cmd/go/internal/work/exec.go:155 +0x12f > created by cmd/go/internal/work.(*Builder).Do > /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a > > goroutine 24 [chan receive]: > cmd/go/internal/base.processSignals.func1(0xc86f00) > /usr/local/go/src/cmd/go/internal/base/signal.go:21 +0x34 > created by cmd/go/internal/base.processSignals > /usr/local/go/src/cmd/go/internal/base/signal.go:20 +0x93 > > rax0x104 > rbx0xea00 > rcx0x7fff5fbff488 > rdx0xea00 > rdi0x1967620 > rsi0xea01eb00 > rbp0x7fff5fbff520 > rsp0x7fff5fbff488 > r8 0x0 > r9 0x60 > r100x0 >
Re: [go-nuts] I found a very strange code that would cause deadlocks and blocking，why???
This is the stack information printed when blocking, how to see which G blocking program? SIGABRT: abort PC=0x7fff9ceabbf2 m=0 sigcode=0 goroutine 0 [idle]: runtime.pthread_cond_wait(0x1967620, 0x19675e0, 0x7fff) /usr/local/go/src/runtime/sys_darwin.go:302 +0x51 runtime.semasleep(0x, 0x7fff5fbff670) /usr/local/go/src/runtime/os_darwin.go:63 +0x85 runtime.notesleep(0x19673e0) /usr/local/go/src/runtime/lock_sema.go:167 +0xe3 runtime.stoplockedm() /usr/local/go/src/runtime/proc.go:2165 +0x8a runtime.schedule() /usr/local/go/src/runtime/proc.go:2565 +0x2d9 runtime.park_m(0xc72480) /usr/local/go/src/runtime/proc.go:2676 +0xae runtime.mcall(0x105722b) /usr/local/go/src/runtime/asm_amd64.s:299 +0x5b goroutine 1 [semacquire]: sync.runtime_Semacquire(0xc27794) /usr/local/go/src/runtime/sema.go:56 +0x39 sync.(*WaitGroup).Wait(0xc27794) /usr/local/go/src/sync/waitgroup.go:130 +0x64 cmd/go/internal/work.(*Builder).Do(0xc00023b0e0, 0xc0003ee3c0) /usr/local/go/src/cmd/go/internal/work/exec.go:174 +0x38e cmd/go/internal/run.runRun(0x195c300, 0xc1e0e0, 0x1, 0x1) /usr/local/go/src/cmd/go/internal/run/run.go:137 +0x55b main.main() /usr/local/go/src/cmd/go/main.go:219 +0x7d4 goroutine 5 [syscall]: os/signal.signal_recv(0x0) /usr/local/go/src/runtime/sigqueue.go:139 +0x9f os/signal.loop() /usr/local/go/src/os/signal/signal_unix.go:23 +0x22 created by os/signal.init.0 /usr/local/go/src/os/signal/signal_unix.go:29 +0x41 goroutine 50 [select]: cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, 0xc0004b0620) /usr/local/go/src/cmd/go/internal/work/exec.go:155 +0x12f created by cmd/go/internal/work.(*Builder).Do /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a goroutine 51 [select]: cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, 0xc0004b0620) /usr/local/go/src/cmd/go/internal/work/exec.go:155 +0x12f created by cmd/go/internal/work.(*Builder).Do /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a goroutine 52 [syscall]: syscall.Syscall6(0x7, 0x12006, 0xc50c24, 0x0, 0xc0002f43f0, 0x0, 0x0, 0xc0002f43f0, 0x0, 0xce2400) /usr/local/go/src/syscall/asm_darwin_amd64.s:41 +0x5 syscall.wait4(0x12006, 0xc50c24, 0x0, 0xc0002f43f0, 0x90, 0x1566d60, 0x14cc401) /usr/local/go/src/syscall/zsyscall_darwin_amd64.go:34 +0x7b syscall.Wait4(0x12006, 0xc50c74, 0x0, 0xc0002f43f0, 0x0, 0x1, 0x1) /usr/local/go/src/syscall/syscall_bsd.go:129 +0x51 os.(*Process).wait(0xc0002fd4a0, 0xc34a00, 0xc50cf8, 0x0) /usr/local/go/src/os/exec_unix.go:38 +0x7b os.(*Process).Wait(0xc0002fd4a0, 0x15b89c8, 0x15b89d0, 0x15b89c0) /usr/local/go/src/os/exec.go:125 +0x2b os/exec.(*Cmd).Wait(0xc00052da20, 0x0, 0x0) /usr/local/go/src/os/exec/exec.go:465 +0x5b os/exec.(*Cmd).Run(0xc00052da20, 0x50, 0xcdf7c0) /usr/local/go/src/os/exec/exec.go:309 +0x5c cmd/go/internal/base.RunStdin(0xcdf7c0, 0x1, 0x1) /usr/local/go/src/cmd/go/internal/base/base.go:162 +0x11e cmd/go/internal/run.buildRunProgram(0xc00023b0e0, 0xc0003ee3c0, 0x13999b3, 0xc00023b150) /usr/local/go/src/cmd/go/internal/run/run.go:151 +0x26d cmd/go/internal/work.(*Builder).Do.func1(0xc0003ee3c0) /usr/local/go/src/cmd/go/internal/work/exec.go:107 +0x72 cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, 0xc0004b0620) /usr/local/go/src/cmd/go/internal/work/exec.go:165 +0xbb created by cmd/go/internal/work.(*Builder).Do /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a goroutine 53 [select]: cmd/go/internal/work.(*Builder).Do.func2(0xc27794, 0xc00023b0e0, 0xc0004b0620) /usr/local/go/src/cmd/go/internal/work/exec.go:155 +0x12f created by cmd/go/internal/work.(*Builder).Do /usr/local/go/src/cmd/go/internal/work/exec.go:152 +0x36a goroutine 24 [chan receive]: cmd/go/internal/base.processSignals.func1(0xc86f00) /usr/local/go/src/cmd/go/internal/base/signal.go:21 +0x34 created by cmd/go/internal/base.processSignals /usr/local/go/src/cmd/go/internal/base/signal.go:20 +0x93 rax0x104 rbx0xea00 rcx0x7fff5fbff488 rdx0xea00 rdi0x1967620 rsi0xea01eb00 rbp0x7fff5fbff520 rsp0x7fff5fbff488 r8 0x0 r9 0x60 r100x0 r110x202 r120x1967620 r130x16 r140x1 r150x7fffa5c9d3c0 rip0x7fff9ceabbf2 rflags 0x203 cs 0x7 fs 0x0 gs 0x0 在 2019年2月28日星期四 UTC+8下午8:44:55，Sameer Ajmani写道： > > The deadlock happens because the channel is empty, so the receive > operation blocks forever. > > The second version imports a package that may start new goroutines in its > init functions. If so, those goroutines may not be deadlocked, but the main > function is still blocked on the receive operation. > > It can be useful to send SIGQUIT to a
Re: [go-nuts] I found a very strange code that would cause deadlocks and blocking，why???
Sameer is correct, but to be clear - The *block* happens because the channel is empty, so the receive operation blocks forever. This happens in both of the cases you show. The *deadlock* happens because *all* goroutines are blocked and none can continue. So if you start some other goroutine that is not blocked, you won't have a deadlock, even though your main routine is blocked forever, which you are inadvertently doing by that import. Or, more to the point, you have a deadlock that Go can't detect as such - because technically, there is a goroutine running that could at some point read from that channel and your main routine would be unblocked and continue. It won't, because it has no reference to it, but the compiler is not currently able to detect that. Again, both cases actually block. It is merely that in the first case the compiler can detect that it is a 'forever-blocked' situation and kills the program with a warning that it was deadlocked. Howard -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [go-nuts] I found a very strange code that would cause deadlocks and blocking，why???
The deadlock happens because the channel is empty, so the receive operation
blocks forever.
The second version imports a package that may start new goroutines in its
init functions. If so, those goroutines may not be deadlocked, but the main
function is still blocked on the receive operation.
It can be useful to send SIGQUIT to a blocked Go program to dump the
goroutine stack traces to the terminal.
S
On Thu, Feb 28, 2019 at 4:19 AM wrote:
> dead lock：
>
> package main
>
> import (
> "fmt"
> // _ "github.com/go-sql-driver/mysql"
> )
>
> func main() {
> c1 := make(chan int, 10)
> fmt.Println(<-c1)
> }
>
>
> block：
>
> package main
>
> import (
> "fmt"
>
> _ "github.com/go-sql-driver/mysql"
> )
>
> func main() {
> c1 := make(chan int, 10)
> fmt.Println(<-c1)
> }
>
> --
> You received this message because you are subscribed to the Google Groups
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> To unsubscribe from this group and stop receiving emails from it, send an
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>
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Re: [go-nuts] I found a very strange code that would cause deadlocks and blocking，why???
ok， thanks！ 在 2019年2月28日星期四 UTC+8下午5:49:48，Jan Mercl写道： > > On Thu, Feb 28, 2019 at 10:20 AM > wrote: > > Please do not post colorized source code, particularly not using low > contrast, inverted color schemes. There are people not able to read it. > Some others may just ignore it or even consider it bad netiquette. > > Black on white is the most universally readable option. Thanks. > > -- > > -j > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [go-nuts] I found a very strange code that would cause deadlocks and blocking，why???
On Thu, Feb 28, 2019 at 10:20 AM wrote: Please do not post colorized source code, particularly not using low contrast, inverted color schemes. There are people not able to read it. Some others may just ignore it or even consider it bad netiquette. Black on white is the most universally readable option. Thanks. -- -j -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[go-nuts] I found a very strange code that would cause deadlocks and blocking，why???
dead lock：
package main
import (
"fmt"
// _ "github.com/go-sql-driver/mysql"
)
func main() {
c1 := make(chan int, 10)
fmt.Println(<-c1)
}
block：
package main
import (
"fmt"
_ "github.com/go-sql-driver/mysql"
)
func main() {
c1 := make(chan int, 10)
fmt.Println(<-c1)
}
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