* Andrea Arcangeli <aarcange@xxxxxxxxxx> wrote: > Now tried with a kernel compile with gcc patched as in prev email > (stock glibc and no glibc environment parameters). Without rebooting > (still plenty of hugepages as usual). > > always: > > real 4m7.280s > real 4m7.520s > > never: > > real 4m13.754s > real 4m14.095s > > So the kernel now builds 2.3% faster. As expected nothing huge here > because of gcc not using several hundred hundred mbytes of ram (unlike > translate.o or other more pathological files), and there's lots of > cpu time spent not just in gcc. > > Clearly this is not done for gcc (but for JVM and other workloads with > larger working sets), but even a kernel build running more than 2% > faster I think is worth mentioning as it confirms we're heading > towards the right direction. Was this done on a native/host kernel? I.e. do everyday kernel hackers gain 2.3% of kbuild performance from this? I find that a very large speedup - it's much more than what i'd have expected. Are you absolutely 100% sure it's real? If yes, it would be nice to underline that by gathering some sort of 'perf stat --repeat 3 --all' kind of always/never comparison of those kernel builds, so that we can see where the +2.3% comes from. I'd expect to see roughly the same instruction count (within noise), but a ~3% reduced cycle count (due to fewer/faster TLB fills). Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>