4 ms·

compiler inspector is fun: https://gcc.godbolt.org/ https://gcc.godbolt.org/ perf related tools on linux: https://perf.wiki.kernel.org/index.php/Main_Page http

compiler inspector is fun: https://gcc.godbolt.org/ https://gcc.godbolt.org/ perf related tools on linux: https://perf.wiki.kernel.org/index.php/Main_Page https://perf.wiki.kernel.org/index.php/Main_Page Didn't read it but it's a well known reference: the dragon book (Compilers: Principles, Techniques, and Tools) 2nd edition has stuff on machine-dependent optimizations (chapters 10 and 11 apparently). Most likely a good read.

astrange 5y ago
The dragon book is a bad compiler book. CPU pipelines are extremely dynamic since the slowest actions affecting them (memory reads) are also the least predictable (depends on what ends up in the cache). So it’s usually not worth trying to control them so precisely, but knowing how the first layers work can be good. For x86 the best resources are Agner Fog’s manuals and then the official Intel/AMD ones.
- vnorilo 5y ago
  Agreed with "usually". When you model pipelines, you must know the cache behaviour of your workload, otherwise it is a waste of time. But when you do, in order to approach theoretical machine limits, you do need airtight core resource utilization in your kinner loops.
optymizer 5y ago
Context for others who may have not read "Compilers" by Aho: it's a great textbook and a wonderful resource to learn about compilers, but I wouldn't call it a "good read". A good read is "The Pragmatic Programmer", for some. The dragon book is raw knowledge and it's filled with proofs. The content in the dragon book is the equivalent of a two semester course on compilers, and that's with a prof and TA. Ideally, to get the full benefit of reading this book, you need to reserve a year of your free time after 5pm and be ready to build an optimizing compiler. It's one of those books that requires your full attention for an extended period of time and you come out the other side a stronger developer, only because it didn't kill you with knowledge. Edit: I realized now you may be saying the 2 chapters (10 and 11) are most likely a good read to learn about optimizations, not that the entire book is a "good read" in general. Makes sense - I'll leave the comment up, with the disclaimer that I'm referring to reading the entire book cover to cover.

astrange 5y ago

The dragon book is a bad compiler book. CPU pipelines are extremely dynamic since the slowest actions affecting them (memory reads) are also the least predictable (depends on what ends up in the cache). So it’s usually not worth trying to control them so precisely, but knowing how the first layers work can be good. For x86 the best resources are Agner Fog’s manuals and then the official Intel/AMD ones.

vnorilo 5y ago
Agreed with "usually". When you model pipelines, you must know the cache behaviour of your workload, otherwise it is a waste of time. But when you do, in order to approach theoretical machine limits, you do need airtight core resource utilization in your kinner loops.

optymizer 5y ago

Context for others who may have not read "Compilers" by Aho: it's a great textbook and a wonderful resource to learn about compilers, but I wouldn't call it a "good read". A good read is "The Pragmatic Programmer", for some. The dragon book is raw knowledge and it's filled with proofs. The content in the dragon book is the equivalent of a two semester course on compilers, and that's with a prof and TA. Ideally, to get the full benefit of reading this book, you need to reserve a year of your free time after 5pm and be ready to build an optimizing compiler. It's one of those books that requires your full attention for an extended period of time and you come out the other side a stronger developer, only because it didn't kill you with knowledge. Edit: I realized now you may be saying the 2 chapters (10 and 11) are most likely a good read to learn about optimizations, not that the entire book is a "good read" in general. Makes sense - I'll leave the comment up, with the disclaimer that I'm referring to reading the entire book cover to cover.