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93 lines
4.0 KiB
Markdown
← [Back to Twitter thread index](../README.md)
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---
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title: "@bmcnett That line of thinking is universal solution to most self-inflicted prob"
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author: "NOTimothyLottes"
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handle: "@NOTimothyLottes"
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post_url: "https://x.com/NOTimothyLottes/status/1857820858162753661"
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post_id: "1857820858162753661"
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timestamp: "2024-11-16 16:19:43"
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post_count: 13
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reply_count: 0
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repost_count: 0
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like_count: 2
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view_count: 134
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---
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# @NOTimothyLottes — @bmcnett That line of thinking is universal solution to most self-inflicted prob
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## Post 1 (2024-11-16 15:12:24)
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[0] What a horrible term 'printf-debugging'
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If you are debugger-free might as well at least be libc-free
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Here is how I work CPU C code without any debugger in my engines, and how it works better than a debugger for me ...
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## Post 2 (2024-11-16 15:15:24) — reply to Post 1
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[1] First I map a '.log' file, so there is no other file IO
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(a.) First half of this file (log2 sized file) contains lines of a fixed 64-character size (with the \n at the end)
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(b.) Second half contains just one 32-bit atomic counter of where to write a line
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## Post 3 (2024-11-16 15:18:27) — reply to Post 2
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[2] So writing a line to this log is 100% overhead-free and lock-free, one just increments the atomic counter, and dumps the comment line in the memory mapped file. Note the 64-byte line size matches a cacheline size, so no contention on the write of the line
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## Post 4 (2024-11-16 15:21:07) — reply to Post 3
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[3] It's ideal for a multi-thread environment, you get correct temporal ordering captured in the log file without any real effect on the scheduling of threads.
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## Post 5 (2024-11-16 15:23:52) — reply to Post 4
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[4] Lines are always in a fixed format
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r|sc.milmic|line_|hex_____|0000000000-|string...
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r ... reload count
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sc.milmic ... time since launch (wraps)
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line ... source line number (single file program)
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hex ... hex print of number
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000 ... decimal print of the number
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string ... user msg
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## Post 6 (2024-11-16 15:25:16) — reply to Post 5
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[5] I write a line with a simple function call
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Tlk(__LINE__,n,"msg");
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Where 'n' is the number, "msg" is a string
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Don't need printf, this is way better
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## Post 7 (2024-11-16 15:35:45) — reply to Post 6
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[6] Here is an example with a very simple program, just a few first lines. It's nice to automatically see exact timing. Timing since start
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0.005478 sec ... mapping of the cartridge file
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0.006850 sec ... page faulting the full cart file
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0.008230 sec ... window creation done
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etc
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## Post 8 (2024-11-16 15:45:00) — reply to Post 7
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[7] Another simple example of a fully pipelined startup, can instantly know where the primary cost is,
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"Instance begin" and "Instance end" wrap setup of the Vulkan instance, a process which took 2.4 seconds. The 4 PSOs hit in the shader cache at 3k microseconds each
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## Post 9 (2024-11-16 15:48:37) — reply to Post 8
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[8] The log file keeps multiple runs, so it's easy to compare. Notepad2 it's F5 to reload the log file.
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## Post 10 (2024-11-16 15:58:30) — reply to Post 9
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@NOTimothyLottes So each line is 63 spaces followed by a \n, and those 63 spaces get replaced by printable characters dynamically? I have long dreamed of a text format with a fixed 128 byte line width, and cache line size is gradually switching over from 64 to 128
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## Post 11 (2024-11-16 16:10:50) — reply to Post 10
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@bmcnett Yes fixed character[63]='\n', string fills until then or spaces out. I did 128-char once, but still sometimes use small VGA resolutions. Also written a source editor a few times with this fixed line size, makes for a very simple implementation ...
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## Post 12 (2024-11-16 16:15:50) — reply to Post 11
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@NOTimothyLottes Variable line width ASCII text files made a lot of sense when storage was 100KB or 100MB or 100GB, but now that it's in the terabytes, why even bother
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## Post 13 (2024-11-16 16:19:43) — reply to Post 12
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@bmcnett That line of thinking is universal solution to most self-inflicted problems of the modern era.
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