Date: Sun, 30 Nov 2003 09:43:05 -0500 From: "Christopher M. Sedore" <cmsedore@maxwell.syr.edu> To: "Jeff Roberson" <jroberson@chesapeake.net> Cc: threads@freebsd.org Subject: RE: KSE system scope vs non system scope threads Message-ID: <32A8B2CB12BFC84D8D11D872C787AA9A02B1F78F@EXCHANGE.forest.maxwell.syr.edu>
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From: Jeff Roberson [mailto:jroberson@chesapeake.net] >> I ask this because I'm observing some behavior that I don't expect. = >> When running a threaded program with KSE and non-system-scope=20 >> threads, I see performance degradation in my network traffic when I'm >> attempting to connect to remote hosts that are down. Libthr doesn't >> see this degradation, and KSE with system-scope threads doesn't >> perform as well as libthr, but is much closer. > >Can you describe the threaded application some? For certain types of >tasks thr is likely to remain faster due to its simplicity. I'm mostly >just curious to hear what your observations are. Sure--I'm working on Usenet news transit software. Basically, inbound = connections offering articles to the host and outbound connections = offering the articles to other hosts. Inbound data rates are usually in = the 6-10MB/sec range (much higher if you have a backlog of articles), = outbound rates depend on the number of peers you have. In testing thus = far, I've been pushing 30MB/sec with my current code. Thus far, libthr = is fastest based on external benchmarks. =20 =20 I think libthr may have a bug related to synchronization somewhere, = though. After some random period, threads hang in sigwait (according to = top). From what I've observed, everything is fine, then one thread = hangs, then shortly thereafter the rest do (actually not all the rest, = but any that content for mutexes do). Since I don't see these hangs = with KSE or libc_r, I've blindly assumed that the problem is with libthr = rather than my code. =20 -Chris
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