[lldb] Print a message when background tasks take a while to complete… #8617
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…llvm#82799) When terminating the debugger, we wait for all background tasks to complete. Given that there's no way to interrupt those treads, this can take a while. When that happens, the debugger appears to hang at exit. The above situation is unfortunately not uncommon when background downloading of dSYMs is enabled (`symbols.auto-download background`). Even when calling dsymForUUID with a reasonable timeout, it can take a while to complete. This patch improves the user experience by printing a message from the driver when it takes more than one (1) second to terminate the debugger. (cherry picked from commit 2f343fc)
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@swift-ci test |
| // than 1 second. | ||
| { | ||
| std::future<void> future = | ||
| std::async(std::launch::async, []() { SBDebugger::Terminate(); }); |
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Is there any risk on calling Terminate() on a different thread (as opposed to printing the message on another thread and terminating in the main thread?
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I can't immediately think of a reason it wouldn't be safe to do, but I didn't look at every single terminator. Doing what you suggest is possible, though it would be slightly more convoluted and slightly less efficient. You'd have to spawn an async task and check periodically whether terminate has completed on the main thread. Something like:
bool terminated = false;
SBDebugger::Terminate();
terminated = true;
std::async(std::launch::async, [&terminated]() {
for (size_t i = 0; i < 10; ++i) {
if (terminated)
return;
std::this_thread::sleep_for(100ms);
}
fprintf(stderr, "Waiting for background tasks to complete...\n");
}
Let me know if you think that's worth the trade-off.
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If you think it's safe, it's fine with me.
JDevlieghere
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jdevlieghere/cherrypick-2f343fc1574f36b3b5ff1acf63407c53dcdac331
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… (llvm#82799)
When terminating the debugger, we wait for all background tasks to complete. Given that there's no way to interrupt those treads, this can take a while. When that happens, the debugger appears to hang at exit.
The above situation is unfortunately not uncommon when background downloading of dSYMs is enabled (
symbols.auto-download background). Even when calling dsymForUUID with a reasonable timeout, it can take a while to complete.This patch improves the user experience by printing a message from the driver when it takes more than one (1) second to terminate the debugger.
(cherry picked from commit 2f343fc)