On Thu, Sep 22, 2016 at 11:28:38AM +0200, Julien Charbon wrote: > >>> What purpose to not skip locked tcptw in this loop? > >> > >> If I understand your question correctly: According to your pmcstat > >> result, tcp_tw_2msl_scan() currently struggles with a write lock > >> (__rw_wlock_hard) and the only write lock used tcp_tw_2msl_scan() is > >> INP_WLOCK. No sign of contention on TW_RLOCK(V_tw_lock) currently. > > > > As I see in code, tcp_tw_2msl_scan got first node from V_twq_2msl and > > need got RW lock on inp w/o alternates. Can tcp_tw_2msl_scan skip current > > node > > and go to next node in V_twq_2msl list if current node locked by some > > reasson? > > Interesting question indeed: It is not optimal that all simultaneous > calls to tcp_tw_2msl_scan() compete for the same oldest tcptw. The next > tcptws in the list are certainly old enough also. > > Let me see if I can make a simple change that makes kernel threads > calling tcp_tw_2msl_scan() at same time to work on a different old > enough tcptws. So far, I found only solutions quite complex to implement.
Simple solution is skip in each thread ncpu elemnts and skip curent cpu number elements at start, if I understund you correctly. _______________________________________________ freebsd-stable@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
