btt/unplug_hist.c

/*
 * blktrace output analysis: generate a timeline & gather statistics
 *
 * Copyright (C) 2006 Alan D. Brunelle <Alan.Brunelle@hp.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
#include "globals.h"

#define BKT_WIDTH	5
#define MAX_BKT		19
#define EXCESS_BKT	20
#define NBKTS		(EXCESS_BKT + 1)

struct hist_bkt {
	__u32 dev;
	int hist[NBKTS * sizeof(int)];
};

void *unplug_hist_alloc(__u32 device)
{
	struct hist_bkt *hbp;

	if (unplug_hist_name == NULL) return NULL;

	hbp = malloc(sizeof(*hbp));
	hbp->dev = device;
	memset(hbp->hist, 0, NBKTS * sizeof(int));

	return hbp;
}

void unplug_hist_add(struct io *u_iop)
{
	struct d_info *dip;

	dip = __dip_find(u_iop->t.device);
	if (dip && dip->up_hist_handle) {
		__u64 *val = u_iop->pdu;
		int idx, n_unplugs = be64_to_cpu(*val);
		struct hist_bkt *hbp = dip->up_hist_handle;

		idx = (n_unplugs / BKT_WIDTH);
		if (idx > EXCESS_BKT)
			idx = EXCESS_BKT;

		hbp->hist[idx]++;
	}
}

void unplug_hist_free(void *arg)
{
	if (arg) {
		FILE *fp;
		struct hist_bkt *hbp = arg;
		int mjr = hbp->dev >> MINORBITS;
		int mnr = hbp->dev & ((1 << MINORBITS) - 1);
		char *oname = malloc(strlen(unplug_hist_name) + 32);

		sprintf(oname, "%s_%03d,%03d.dat", unplug_hist_name, mjr, mnr);
		if ((fp = my_fopen(oname, "w")) != NULL) {
			int i;

			for (i = 0; i < NBKTS; i++)
				fprintf(fp, "%d %d\n", i, hbp->hist[i]);
			fclose(fp);

		} else
			perror(oname);

		free(oname);
		free(hbp);
	}
}