On Wed, Jul 1, 2020, at 1:40 AM, Fabian Groffen wrote: > On 30-06-2020 13:13:29 -0500, Sid Spry wrote: > > On Tue, Jun 30, 2020, at 1:20 AM, Fabian Groffen wrote: > > > Hi, > > > > > > On 29-06-2020 21:13:43 -0500, Sid Spry wrote: > > > > Hello, > > > > > > > > I have some runnable pseudocode outlining a faster tree verification > > > > algorithm. > > > > Before I create patches I'd like to see if there is any guidance on > > > > making the > > > > changes as unobtrusive as possible. If the radical change in algorithm > > > > is > > > > acceptable I can work on adding the changes. > > > > > > > > Instead of composing any kind of structured data out of the portage > > > > tree my > > > > algorithm just lists all files and then optionally batches them out to > > > > threads. > > > > There is a noticeable speedup by eliding the tree traversal operations > > > > which > > > > can be seen when running the algorithm with a single thread and > > > > comparing it to > > > > the current algorithm in gemato (which should still be discussed here?). > > > > > > I remember something that gemato used to use multiple threads, but > > > because it totally saturated disk-IO, it was brought back to a single > > > thread. People were complaining about unusable systems. > > > > > > > I think this is an argument for cgroups limits support on the portage > > process or > > account as opposed to an argument against picking a better algorithm. That > > is > > something I have been working towards, but I am only one man. > > But this requires a) cgroups support, and b) the privileges to use it. > Shouldn't be a problem in the normal case, but just saying. >
cgroups kernel support is a fairly common dependency. It can obviously be optional, I am thinking related to MAKEOPTS or EMERGE_DEFAULT_OPTS (see: rustc/cargo not respecting or being passed -j/-l as another use for cgroups) and supported best-effort, but is there any reason to expect it to not be enabled? If the user isn't either root or portage I think it reasonable to leave resource management to the machine's administrator.
