From f8ad22919e217e5aa0f3f7a246fc37aaee182364 Mon Sep 17 00:00:00 2001 From: luigi Date: Fri, 14 Dec 2001 17:56:12 +0000 Subject: Device Polling code for -current. Non-SMP, i386-only, no polling in the idle loop at the moment. To use this code you must compile a kernel with options DEVICE_POLLING and at runtime enable polling with sysctl kern.polling.enable=1 The percentage of CPU reserved to userland can be set with sysctl kern.polling.user_frac=NN (default is 50) while the remainder is used by polling device drivers and netisr's. These are the only two variables that you should need to touch. There are a few more parameters in kern.polling but the default values are adequate for all purposes. See the code in kern_poll.c for more details on them. Polling in the idle loop will be implemented shortly by introducing a kernel thread which does the job. Until then, the amount of CPU dedicated to polling will never exceed (100-user_frac). The equivalent (actually, better) code for -stable is at http://info.iet.unipi.it/~luigi/polling/ and also supports polling in the idle loop. NOTE to Alpha developers: There is really nothing in this code that is i386-specific. If you move the 2 lines supporting the new option from sys/conf/{files,options}.i386 to sys/conf/{files,options} I am pretty sure that this should work on the Alpha as well, just that I do not have a suitable test box to try it. If someone feels like trying it, I would appreciate it. NOTE to other developers: sure some things could be done better, and as always I am open to constructive criticism, which a few of you have already given and I greatly appreciated. However, before proposing radical architectural changes, please take some time to possibly try out this code, or at the very least read the comments in kern_poll.c, especially re. the reason why I am using a soft netisr and cannot (I believe) replace it with a simple timeout. Quick description of files touched by this commit: sys/conf/files.i386 new file kern/kern_poll.c sys/conf/options.i386 new option sys/i386/i386/trap.c poll in trap (disabled by default) sys/kern/kern_clock.c initialization and hardclock hooks. sys/kern/kern_intr.c minor swi_net changes sys/kern/kern_poll.c the bulk of the code. sys/net/if.h new flag sys/net/if_var.h declaration for functions used in device drivers. sys/net/netisr.h NETISR_POLL sys/dev/fxp/if_fxp.c sys/dev/fxp/if_fxpvar.h sys/pci/if_dc.c sys/pci/if_dcreg.h sys/pci/if_sis.c sys/pci/if_sisreg.h device driver modifications --- sys/kern/kern_intr.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'sys/kern/kern_intr.c') diff --git a/sys/kern/kern_intr.c b/sys/kern/kern_intr.c index e873c6e..88868dc 100644 --- a/sys/kern/kern_intr.c +++ b/sys/kern/kern_intr.c @@ -623,7 +623,16 @@ swi_net(void *dummy) u_int bits; int i; +#ifdef DEVICE_POLLING + for (;;) { + int pollmore; +#endif bits = atomic_readandclear_int(&netisr); +#ifdef DEVICE_POLLING + if (bits == 0) + return; + pollmore = bits & (1 << NETISR_POLL); +#endif while ((i = ffs(bits)) != 0) { i--; if (netisrs[i] != NULL) @@ -632,6 +641,11 @@ swi_net(void *dummy) printf("swi_net: unregistered isr number: %d.\n", i); bits &= ~(1 << i); } +#ifdef DEVICE_POLLING + if (pollmore) + ether_pollmore(); + } +#endif } /* -- cgit v1.1