4 ms·

It would be difficult as every package/program would need a step to generate the profile data by executing and running the program like the user would.

metadat 2y ago
Is it theoretically possible to perform the profile generation+apply steps dynamically at runtime?
- cryptonector 2y ago
  It would be hard to trust the result.
- tjalfi 2y ago
  I wouldn't want to support it, but similar things have been done before. Alexia Massalin's Synthesis[0] (pdf) operating system did JIT-like optimizations for system calls. Here's a LWN article[1] with a summary. Anyone who's interested in operating systems should read this thesis. HP's Dynamo[2] runtime optimizer did JIT-like optimizations on PA-RISC binaries; it was released in 2000. DynamoRIO[3] is an open source descendant. Also, DEC had a similar tool for the Alpha, but I've forgotten the name. [0] https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=1467a614509e49995a213a138f86c81b43f4cd56 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&d... [1] https://lwn.net/Articles/270081/ https://lwn.net/Articles/270081/ [2] https://dl.acm.org/doi/pdf/10.1145/349299.349303 https://dl.acm.org/doi/pdf/10.1145/349299.349303 [3] https://dynamorio.org/ https://dynamorio.org/
  - hikarikuen 2y ago
    This is getting way outside the traditional compiler model, but I believe the .NET JIT has been adding more support for this in the last couple versions. One aspect of it is covered at https://devblogs.microsoft.com/dotnet/performance-improvements-in-net-8/#tiering-and-dynamic-pgo https://devblogs.microsoft.com/dotnet/performance-improvemen...
  - EvanAnderson 2y ago
    Nat Freidman developed "GNU Rope"[1] from 1998 which, if memory serves, was inspired by a tool that did the same thing in IRIX (cord, I believe). [1] http://lwn.net/1998/1029/als/rope.html http://lwn.net/1998/1029/als/rope.html
- pgaddict 2y ago
  I believe some JIT systems already do PGO / might be extended to do what BOLT does.

metadat 2y ago

Is it theoretically possible to perform the profile generation+apply steps dynamically at runtime?

cryptonector 2y ago
It would be hard to trust the result.
tjalfi 2y ago
I wouldn't want to support it, but similar things have been done before. Alexia Massalin's Synthesis[0] (pdf) operating system did JIT-like optimizations for system calls. Here's a LWN article[1] with a summary. Anyone who's interested in operating systems should read this thesis. HP's Dynamo[2] runtime optimizer did JIT-like optimizations on PA-RISC binaries; it was released in 2000. DynamoRIO[3] is an open source descendant. Also, DEC had a similar tool for the Alpha, but I've forgotten the name. [0] https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=1467a614509e49995a213a138f86c81b43f4cd56 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&d... [1] https://lwn.net/Articles/270081/ https://lwn.net/Articles/270081/ [2] https://dl.acm.org/doi/pdf/10.1145/349299.349303 https://dl.acm.org/doi/pdf/10.1145/349299.349303 [3] https://dynamorio.org/ https://dynamorio.org/
- hikarikuen 2y ago
  This is getting way outside the traditional compiler model, but I believe the .NET JIT has been adding more support for this in the last couple versions. One aspect of it is covered at https://devblogs.microsoft.com/dotnet/performance-improvements-in-net-8/#tiering-and-dynamic-pgo https://devblogs.microsoft.com/dotnet/performance-improvemen...
- EvanAnderson 2y ago
  Nat Freidman developed "GNU Rope"[1] from 1998 which, if memory serves, was inspired by a tool that did the same thing in IRIX (cord, I believe). [1] http://lwn.net/1998/1029/als/rope.html http://lwn.net/1998/1029/als/rope.html
pgaddict 2y ago
I believe some JIT systems already do PGO / might be extended to do what BOLT does.