Merge bitcoin/bitcoin#23302: tracing: drop GetHash().ToString() argument from the `validation:block_connected` tracepoint

53c9fa9e6253ea89ba1057b35e018ad1a25fb97e tracing: drop block_connected hash.toString() arg (0xb10c)

Pull request description:

  The tracepoint `validation:block_connected` was introduced in #22006.
  The first argument was the hash of the connected block as a pointer
  to a C-like String. The last argument passed the hash of the
  connected block as a pointer to 32 bytes. The hash was only passed as
  string to allow `bpftrace` scripts to print the hash. It was
  (incorrectly) assumed that `bpftrace` cannot hex-format and print the
  block hash given only the hash as bytes.

  The block hash can be printed in `bpftrace` by calling
  `printf("%02x")` for each byte of the hash in an `unroll () {...}`.
  By starting from the last byte of the hash, it can be printed in
  big-endian (the block-explorer format).

  ```C
    $p = $hash + 31;
    unroll(32) {
        $b = *(uint8*)$p;
        printf("%02x", $b);
        $p -= 1;
    }
  ```

  See also: #22902 (comment)

  This is a breaking change to the block_connected tracepoint API, however
  this tracepoint has not yet been included in a release.

ACKs for top commit:
  laanwj:
    Concept and code review ACK 53c9fa9e6253ea89ba1057b35e018ad1a25fb97e
  jb55:
    ACK 53c9fa9e6253ea89ba1057b35e018ad1a25fb97e

Tree-SHA512: f1b9e4e0ee45aae892e8bf38e04b5ee5fbc643d6e7e27d011b829ed8701dacf966a99b7c877c46cca8666b894a375633e62582c552c8203614c6f2b9c4087585

1 files changed, 1 insertions, 8 deletions

diff --git a/doc/tracing.md b/doc/tracing.md
index 87fc9603fe..57104c43a0 100644
--- a/doc/tracing.md
+++ b/doc/tracing.md
@@ -101,19 +101,12 @@ Is called *after* a block is connected to the chain. Can, for example, be used
 to benchmark block connections together with `-reindex`.
 
 Arguments passed:
-1. Block Header Hash as `pointer to C-style String` (64 characters)
+1. Block Header Hash as `pointer to unsigned chars` (i.e. 32 bytes in little-endian)
 2. Block Height as `int32`
 3. Transactions in the Block as `uint64`
 4. Inputs spend in the Block as `int32`
 5. SigOps in the Block (excluding coinbase SigOps) `uint64`
 6. Time it took to connect the Block in microseconds (µs) as `uint64`
-7. Block Header Hash as `pointer to unsigned chars` (i.e. 32 bytes in little-endian)
-
-Note: The 7th argument can't be accessed by bpftrace and is purposefully chosen
-to be the block header hash as bytes. See [bpftrace argument limit] for more
-details.
-
-[bpftrace argument limit]: #bpftrace-argument-limit
 
 ## Adding tracepoints to Bitcoin Core