From f13593619b074dff63f6940d32033d2f147166e3 Mon Sep 17 00:00:00 2001 From: Alexander Motin Date: Tue, 7 Nov 2023 14:35:40 -0500 Subject: [PATCH] FreeBSD: Optimize large kstat outputs - Use sbuf_new_for_sysctl() to reduce double-buffering on sysctl output. - Use much faster sbuf_cat() instead of sbuf_printf("%s"). Together it reduces `sysctl kstat.zfs.misc.dbufs` time from minutes to seconds, making dbufstat almost usable. Reviewed-by: Brian Behlendorf Signed-off-by: Alexander Motin Sponsored by: iXsystems, Inc. Closes #15495 --- module/os/freebsd/spl/spl_kstat.c | 38 +++++++++++++------------------ 1 file changed, 16 insertions(+), 22 deletions(-) diff --git a/module/os/freebsd/spl/spl_kstat.c b/module/os/freebsd/spl/spl_kstat.c index 9f5f92e194..43cd4da02e 100644 --- a/module/os/freebsd/spl/spl_kstat.c +++ b/module/os/freebsd/spl/spl_kstat.c @@ -187,19 +187,18 @@ kstat_sysctl_dataset_string(SYSCTL_HANDLER_ARGS) static int kstat_sysctl_io(SYSCTL_HANDLER_ARGS) { - struct sbuf *sb; + struct sbuf sb; kstat_t *ksp = arg1; kstat_io_t *kip = ksp->ks_data; int rc; - sb = sbuf_new_auto(); - if (sb == NULL) - return (ENOMEM); + sbuf_new_for_sysctl(&sb, NULL, 0, req); + /* Update the aggsums before reading */ (void) ksp->ks_update(ksp, KSTAT_READ); /* though wlentime & friends are signed, they will never be negative */ - sbuf_printf(sb, + sbuf_printf(&sb, "%-8llu %-8llu %-8u %-8u %-8llu %-8llu " "%-8llu %-8llu %-8llu %-8llu %-8u %-8u\n", kip->nread, kip->nwritten, @@ -207,25 +206,21 @@ kstat_sysctl_io(SYSCTL_HANDLER_ARGS) kip->wtime, kip->wlentime, kip->wlastupdate, kip->rtime, kip->rlentime, kip->rlastupdate, kip->wcnt, kip->rcnt); - rc = sbuf_finish(sb); - if (rc == 0) - rc = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb)); - sbuf_delete(sb); + rc = sbuf_finish(&sb); + sbuf_delete(&sb); return (rc); } static int kstat_sysctl_raw(SYSCTL_HANDLER_ARGS) { - struct sbuf *sb; + struct sbuf sb; void *data; kstat_t *ksp = arg1; void *(*addr_op)(kstat_t *ksp, loff_t index); int n, has_header, rc = 0; - sb = sbuf_new_auto(); - if (sb == NULL) - return (ENOMEM); + sbuf_new_for_sysctl(&sb, NULL, PAGE_SIZE, req); if (ksp->ks_raw_ops.addr) addr_op = ksp->ks_raw_ops.addr; @@ -258,8 +253,10 @@ restart_headers: if (has_header) { if (rc == ENOMEM && !kstat_resize_raw(ksp)) goto restart_headers; - if (rc == 0) - sbuf_printf(sb, "\n%s", ksp->ks_raw_buf); + if (rc == 0) { + sbuf_cat(&sb, "\n"); + sbuf_cat(&sb, ksp->ks_raw_buf); + } } while ((data = addr_op(ksp, n)) != NULL) { @@ -270,22 +267,19 @@ restart: if (rc == ENOMEM && !kstat_resize_raw(ksp)) goto restart; if (rc == 0) - sbuf_printf(sb, "%s", ksp->ks_raw_buf); + sbuf_cat(&sb, ksp->ks_raw_buf); } else { ASSERT3U(ksp->ks_ndata, ==, 1); - sbuf_hexdump(sb, ksp->ks_data, + sbuf_hexdump(&sb, ksp->ks_data, ksp->ks_data_size, NULL, 0); } n++; } free(ksp->ks_raw_buf, M_TEMP); mutex_exit(ksp->ks_lock); - sbuf_trim(sb); - rc = sbuf_finish(sb); - if (rc == 0) - rc = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb)); - sbuf_delete(sb); + rc = sbuf_finish(&sb); + sbuf_delete(&sb); return (rc); }