Messages in this thread | | | Date | Tue, 24 Sep 2002 00:05:39 +1000 | From | Rusty Russell <> | Subject | Re: [chatroom benchmark version 1.0.1] Results |
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On Thu, 19 Sep 2002 01:29:30 -0700 Andrew Morton <akpm@digeo.com> wrote:
> Daniel Phillips wrote: > > > > Just thought I'd bounce this one over to Andrew as a warm-n-fuzzy. > > Is a scheduler test, isn't it?
Mixed. Before the O(1) scheduler, I distilled this test into "hackbench" (which I now call schedbench). Do well on this, and you'll do well on the lots-of-threads-wakingup case: [BTW, 2.5 rocks at this 8)]. Ideally "hackbench n" should scale with n:
/* Test groups of 20 processes spraying to 20 receivers */ #include <stdio.h> #include <string.h> #include <errno.h> #include <sys/types.h> #include <sys/socket.h> #include <sys/wait.h> #include <sys/time.h> #include <sys/select.h>
#define DATASIZE 100 static unsigned int loops = 100; static int use_pipes = 0;
static void barf(const char *msg) { fprintf(stderr, "%s (error: %s)\n", msg, strerror(errno)); exit(1); }
static void fdpair(int fds[2]) { if (use_pipes) { if (pipe(fds) == 0) return; } else { if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) == 0) return; } barf("Creating fdpair"); }
/* Block until we're ready to go */ static void ready(int ready_out, int wakefd) { char dummy; fd_set fds;
FD_ZERO(&fds); FD_SET(wakefd, &fds);
/* Tell them we're ready. */ if (write(ready_out, &dummy, 1) != 1) barf("CLIENT: ready write");
/* Wait for "GO" signal */ if (select(wakefd+1, &fds, NULL, NULL, NULL) != 1) barf("select"); }
/* Sender sprays loops messages down each file descriptor */ static void sender(unsigned int num_fds, int out_fd[num_fds], int ready_out, int wakefd) { char data[DATASIZE]; unsigned int i, j;
ready(ready_out, wakefd);
/* Now pump to every receiver. */ for (i = 0; i < loops; i++) { for (j = 0; j < num_fds; j++) { int ret, done = 0;
again: ret = write(out_fd[j], data + done, sizeof(data)-done); if (ret < 0) barf("SENDER: write"); done += ret; if (done < sizeof(data)) goto again; } } }
/* One receiver per fd */ static void receiver(unsigned int num_packets, int in_fd, int ready_out, int wakefd) { unsigned int i;
/* Wait for start... */ ready(ready_out, wakefd);
/* Receive them all */ for (i = 0; i < num_packets; i++) { char data[DATASIZE]; int ret, done = 0;
again: ret = read(in_fd, data + done, DATASIZE - done); if (ret < 0) barf("SERVER: read"); done += ret; if (done < DATASIZE) goto again; } }
/* One group of senders and receivers */ static unsigned int group(unsigned int num_fds, int ready_out, int wakefd) { unsigned int i; unsigned int out_fds[num_fds];
for (i = 0; i < num_fds; i++) { int fds[2];
/* Create the pipe between client and server */ fdpair(fds);
/* Fork the receiver. */ switch (fork()) { case -1: barf("fork()"); case 0: close(fds[1]); receiver(num_fds*loops, fds[0], ready_out, wakefd); exit(0); }
out_fds[i] = fds[1]; close(fds[0]); }
/* Now we have all the fds, fork the senders */ for (i = 0; i < num_fds; i++) { switch (fork()) { case -1: barf("fork()"); case 0: sender(num_fds, out_fds, ready_out, wakefd); exit(0); } }
/* Close the fds we have left */ for (i = 0; i < num_fds; i++) close(out_fds[i]);
/* Return number of children to reap */ return num_fds * 2; }
int main(int argc, char *argv[]) { unsigned int i, num_groups, total_children; struct timeval start, stop, diff; unsigned int num_fds = 20; int readyfds[2], wakefds[2]; char dummy;
if (argv[1] && strcmp(argv[1], "-pipe") == 0) { use_pipes = 1; argc--; argv++; }
if (argc != 2 || (num_groups = atoi(argv[1])) == 0) barf("Usage: hackbench [-pipe] <num groups>\n");
fdpair(readyfds); fdpair(wakefds);
total_children = 0; for (i = 0; i < num_groups; i++) total_children += group(num_fds, readyfds[1], wakefds[0]);
/* Wait for everyone to be ready */ for (i = 0; i < total_children; i++) if (read(readyfds[0], &dummy, 1) != 1) barf("Reading for readyfds");
gettimeofday(&start, NULL);
/* Kick them off */ if (write(wakefds[1], &dummy, 1) != 1) barf("Writing to start them");
/* Reap them all */ for (i = 0; i < total_children; i++) { int status; wait(&status); if (!WIFEXITED(status)) exit(1); }
gettimeofday(&stop, NULL);
/* Print time... */ timersub(&stop, &start, &diff); printf("Time: %lu.%03lu\n", diff.tv_sec, diff.tv_usec/1000); exit(0); }
-- there are those who do and those who hang on and you don't see too many doers quoting their contemporaries. -- Larry McVoy - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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