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publish TID in 2 formats known formats on a crash #1008

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publish TID in 2 formats known formats on a crash #1008

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2 changes: 2 additions & 0 deletions src/signalhandler.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -211,6 +211,8 @@ void DumpSignalInfo(int signal_number, siginfo_t *siginfo) {
pthread_t id = pthread_self();
formatter.AppendUint64(
reinterpret_cast<uint64>(reinterpret_cast<const char*>(id)), 16);
formatter.AppendString("/");
formatter.AppendUint64(static_cast<uint64>(GetTID()), 10);
Comment on lines +214 to +215
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I would suggest using a format similar to the backtrace. Instead of delineating the PID and TID by /, a PID (TID) formatting (TID being to base 16 with the 0x prefix) seems to be more appropriate.

Suggested change
formatter.AppendString("/");
formatter.AppendUint64(static_cast<uint64>(GetTID()), 10);
formatter.AppendString(" (");
formatter.AppendUint64(static_cast<uint64>(GetTID()), 16);
formatter.AppendString(")");

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@amandeepgautam amandeepgautam Dec 31, 2023 •
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Doing it in base 16 may not be ideal as glog internally publishes base 10 POSIX thread IDs. For example, a line would be:

I1231 01:02:58.835251 1681 kkkk.cc:1591] kkkkkk

So, if I use 0x format, one would have to convert it to 1681 (which would be one more step) to know which thread ID it was.

Let me know what you think.

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Additionally, in the suggested format we would have 2 nested parenthesis like:
(TID 0x7f7666a8b980 (0x2f424...))

I find 2 nested brackets slightly odd. But am okay with what you say.

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Or we can modify the comment to be:
received by PID 2216 in kernel thread ID 0x7f7666a8b980 (POSXI ID: <...>) from PID 2216

from the current version:
received by PID 2216 (TID 0x7f7666a8b980) from PID 2216

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I only referred to TID to be base 16 which is the format currently used by glog. The base 10 format of POSIX thread ID should remain. It is important that the format is consistent throughout with respect to radix, ID order, possible labels, etc.

Nested parentheses are of course best avoided. You can merge the identifiers and put them into a single pair of round brackets joined by , (comma and a single space).

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@amandeepgautam amandeepgautam Dec 31, 2023 •
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I only referred to TID to be base 16 which is the format currently used by glog. The base 10 format of POSIX thread ID should remain.

I am slightly confused now. Please bear with me as I am not familiar with the codebase. As per this line, GetTID seems to be the one returning unsigned int. So static_cast<uint64>(GetTID()), 10); which is my original implementation seems reasonable. In the suggestion in the comment, we have static_cast<uint64>(GetTID()), 16); which seems to be suggesting that I should convert it to base16, which is not my intention. Can you please let me know what am I missing?

Nested parentheses are of course best avoided. You can merge the identifiers and put them into a single pair of round brackets joined by , (comma and a single space).

Ack.

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Yes, you are correct. I looked through the code and the TID formatting is indeed inconsistent. I therefore suggest keeping the existing format variants and use base 10 representation for the kernel thread IDs consistently instead.

Please note that #1019 removed the use of POSIX threads. There are now conflicts in your branch which you should rebase and resolve.

formatter.AppendString(") ");
// Only linux has the PID of the signal sender in si_pid.
#ifdef GLOG_OS_LINUX
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