* Eric Dumazet <dada1@xxxxxxxxxxxxx> wrote: > Ingo Molnar a écrit : >> * Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx> wrote: >> >>> hmmm... Well we are almost there. >>> >>> 2.6.22: >>> >>> Throughput 2526.15 MB/sec 8 procs >>> >>> 2.6.28-rc5: >>> >>> Throughput 2486.2 MB/sec 8 procs >>> >>> 8p Dell 1950 and the number of processors specified on the tbench >>> command line. >> >> And with net-next we might even be able to get past that magic limit? >> net-next is linus-latest plus the latest and greatest networking bits: >> >> $ cat .git/config >> >> [remote "net-next"] >> url = git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6.git >> fetch = +refs/heads/*:refs/remotes/net-next/* >> >> ... so might be worth a test. Just to satisfy our curiosity and to >> possibly close the entry :-) >> > > Well, bits in net-next are new stuff for 2.6.29, not really > regression fixes, but yes, they should give nice tbench speedups. yeah, i know - technically these are lots-of-kernel-releases effects so not bona fide latest-cycle regressions anyway. But it doesnt matter how we call them, we want improvement in these metrics. > Now, I wish sockets and pipes not going through dcache, not tbench > affair of course but real workloads... > > running 8 processes on a 8 way machine doing a > > for (;;) > close(socket(AF_INET, SOCK_STREAM, 0)); > > is slow as hell, we hit so many contended cache lines ... > > ticket spin locks are slower in this case (dcache_lock for example > is taken twice when we allocate a socket(), once in d_alloc(), > another one in d_instantiate()) hm, weird - since there's no real VFS namespace impact i fail to realize the fundamental need that causes us to hit the dcache_lock. (perhaps there's none and this is fixable) The general concept of mapping sockets to fds is a fundamental and powerful abstraction. There are APIs that also connect them to the VFS namespace (such as unix domain sockets) - but those should be special cases, not impacting normal TCP sockets. Ingo -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
