On Sat, Aug 13, 2022 at 07:23:40PM -0400, Elad Lahav wrote: > I believe that performance is statistically the same, but I will > double check. I assume both GCC and C11 end up using the same > underlying mechanism for thread-local storage: > > https://uclibc.org/docs/tls.pdf > > If not implemented, TLS falls back on pthread_[gs]et_specific(), but > again it would be the same for __thread and _Thread_local. Sounds likely to me, but I have been surprised before. > I was about to run all benchmarks on a cute 16-core aarch64 machine I > recently bought for testing the scalability of my latest kernel work, > but the code requires linking against urcu, and now I'm going down the > rabbit hole of building that for QNX. Does the counter code really > need this library? Only for one of the count programs, count_end_rcu.c. If you comment that one out of the Makefile, you should be fine. Some other adjustments to other files might be needed, for example, CodeSamples/Makefile. Probably about the same amount of work to wean CodeSamples/count from that library as to get it working on QNX. Murphy would of course argue that whichever path you choose will be the harder of the two. Thanx, Paul > --Elad > > On Sat, 13 Aug 2022 at 19:12, Paul E. McKenney <paulmck@xxxxxxxxxx> wrote: > > > > On Sat, Aug 13, 2022 at 07:49:27AM -0400, Elad Lahav wrote: > > > On 2022-08-13 07:45, Elad Lahav wrote: > > > > Signed-off-by: Elad Lahav <e2lahav@xxxxxxxxx> > > > > --- > > > > > > This one will probably require some back-and-forth. If we change it here, do > > > other places need to be updated? Have I now removed the explanation of GCC's > > > __thread storage class, which will impact the readability of other sections? > > > Or are you ready to take the plunge and convert all code snippets? > > > > > > For the record, I did build and test count_end.c. > > > > As long as you continue building and testing, checking the descriptions in > > text of the code snippets (in case there is a mention of __thread there), > > and verifying that the PDF still builds, as fast as you are willing to go! > > > > Are you seeing the same performance with the new as with the old on > > your hardware? (No statistically significant difference on my laptop, > > but figured I should ask.) > > > > Thanx, Paul
