Forgot to add more details in previous mail Here are the more details about debug where i collect a Linux perf of problematic ld process and verify that it's spending most of the extra time in '*lang_output_section_statement_lookup*':-
Here are the key findings from the perf report: *Samples: 15M of event 'cycles', Event count (approx.): 22646358592852* * Children Self Command Shared Object Symbol* *+ 96.86% 96.80% ld ld ** [.] lang_output_section_statement_lookup* As we can see, both the *Children* and *Self* percentages for this function are almost identical, indicating that the function is directly responsible for the majority of the CPU cycles during the linking process. Hence this function is likely causing the hang or performance bottleneck that we are observing. On Thu, Oct 3, 2024 at 9:36 AM Naveen Kumar <kumar.naveen...@gmail.com> wrote: > Hi Team, > > We have recently upgraded binutis from 2.29 version to 2.36 and noticed > that 'Debug' flavor builds are getting hang for a long time during the > linking step. > > We are following partial linking (ld -r) approach in our build process as > mentioned here :- > https://stackoverflow.com/questions/29391965/what-is-partial-linking-in-gnu-linker > > Since we deal with huge source code about 100's of obj files where the > static library size is getting huge, To Workaround it we are using partial > linking which eliminates a lot of duplication. So we are basically creating > a *.o* file out of a partial linking mechanism and using that .o file to > create a '*.a*' static library. > > *Issue:- *With linker (ld) from binutils 2.36 version, Partial linking > step is taking around 60 mins to complete for debug flavor builds. > > We have narrowed down the issue by cloning binutins git repository and > performed 'git bisect' to find exact regression causing SHA-ID and noticed > that this :- > *https://github.com/bminor/binutils-gdb/commit/21401fc7bf67dbf73f4a3eda4bcfc58fa4211584 > <https://github.com/bminor/binutils-gdb/commit/21401fc7bf67dbf73f4a3eda4bcfc58fa4211584>* > is the regression causing change. > > The SHA-ID just before the problematic one does not cause any issues where > linker(ld) command just finished in 1.5 to 2mins. But the culprit CL that > follows is causing the build hangs and linker 'ld' command took nearly > 65mins to complete. > > Please take a look! > Let me know if you still need anything from me. >
