README: list used hashing algorithms, add benchmark results

README.md

@@ -5,9 +5,27 @@ In the context of the project [GNU/Linux System files on-boot Tamper Detection S
 ## Current performance properties
 
 - Reads file system metadata from the main thread (stat, xattrs (SELinux, ..), POSIX ACLs)
-- Reads files and hashes them across multiple processes (as many as core count) with the `multiprocessing` python module
+- Reads files and hashes them in md5, sha1, sha256 and sha512 across multiple processes (as many as core count) with the `multiprocessing` python module
 - Maximizes disk I/O utilization successfully, the Python code's performance is not a bottleneck, the disk is (good sign)
 
+Tested on a laptop with:
+- 3.2 GB/s read NVMe SSD
+- Intel(R) Core(TM) i7-1065G7 CPU (4 cores, 8 threads) @ 1.30 GHz min / 3.90 GHz max
+  - 2 GHz per thread on average under full multithreaded load due to heat and unoptimal laptop thermals (Dell XPS 13 2020)
+
+- For ~1 million files on EXT4 over LUKS+LVM and ~140GB occupied disk space:
+    ```
+    real	6m11.532s
+    user	31m7.676s
+    sys	3m27.251s
+    ```
+
+6 minutes and 12 seconds of real world time
+
+This will hardly get any better because the disk is the bottleneck, CPU usage is not full but disk I/O utilization is, peaking at 500 MB/s reads for these test conditions. 3.2 GB/s on this SSD is for sequential reads (optimal conditions).
+
+It can and probably will be faster on performant servers with less files, less disk space usage, more CPU cores and similar disk.
+
 ## Desired performance properties
 
 - Reduce memory usage