From a68a0a352a0209467268dfddffe02db08b97ddb4 Mon Sep 17 00:00:00 2001 From: Bob Peterson Date: Fri, 19 Oct 2012 08:32:51 -0400 Subject: GFS2: Speed up gfs2_rbm_from_block This patch is a rewrite of function gfs2_rbm_from_block. Rather than looping to find the right bitmap, the code now does a few simple math calculations. I compared the performance of both algorithms side by side and the new algorithm is noticeably faster. Sample instrumentation output from a "fast" machine: 5 million calls: millisec spent: Orig: 166 New: 113 5 million calls: millisec spent: Orig: 189 New: 114 In addition, I ran postmark (on a somewhat slowr CPU) before the after the new algorithm was put in place and postmark showed a decent improvement: Before the new algorithm: ------------------------- Time: 645 seconds total 584 seconds of transactions (171 per second) Files: 150087 created (232 per second) Creation alone: 100000 files (2083 per second) Mixed with transactions: 50087 files (85 per second) 49995 read (85 per second) 49991 appended (85 per second) 150087 deleted (232 per second) Deletion alone: 100174 files (7705 per second) Mixed with transactions: 49913 files (85 per second) Data: 273.42 megabytes read (434.08 kilobytes per second) 852.13 megabytes written (1.32 megabytes per second) With the new algorithm: ----------------------- Time: 599 seconds total 530 seconds of transactions (188 per second) Files: 150087 created (250 per second) Creation alone: 100000 files (1886 per second) Mixed with transactions: 50087 files (94 per second) 49995 read (94 per second) 49991 appended (94 per second) 150087 deleted (250 per second) Deletion alone: 100174 files (6260 per second) Mixed with transactions: 49913 files (94 per second) Data: 273.42 megabytes read (467.42 kilobytes per second) 852.13 megabytes written (1.42 megabytes per second) Signed-off-by: Bob Peterson Signed-off-by: Steven Whitehouse --- fs/gfs2/rgrp.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) (limited to 'fs/gfs2/rgrp.c') diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index 38fe18f2f055..669b89b95ccc 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -251,22 +251,25 @@ static u32 gfs2_bitfit(const u8 *buf, const unsigned int len, static int gfs2_rbm_from_block(struct gfs2_rbm *rbm, u64 block) { u64 rblock = block - rbm->rgd->rd_data0; - u32 goal = (u32)rblock; - int x; + u32 x; if (WARN_ON_ONCE(rblock > UINT_MAX)) return -EINVAL; if (block >= rbm->rgd->rd_data0 + rbm->rgd->rd_data) return -E2BIG; - for (x = 0; x < rbm->rgd->rd_length; x++) { - rbm->bi = rbm->rgd->rd_bits + x; - if (goal < (rbm->bi->bi_start + rbm->bi->bi_len) * GFS2_NBBY) { - rbm->offset = goal - (rbm->bi->bi_start * GFS2_NBBY); - break; - } - } + rbm->bi = rbm->rgd->rd_bits; + rbm->offset = (u32)(rblock); + /* Check if the block is within the first block */ + if (rbm->offset < (rbm->bi->bi_start + rbm->bi->bi_len) * GFS2_NBBY) + return 0; + /* Adjust for the size diff between gfs2_meta_header and gfs2_rgrp */ + rbm->offset += (sizeof(struct gfs2_rgrp) - + sizeof(struct gfs2_meta_header)) * GFS2_NBBY; + x = rbm->offset / rbm->rgd->rd_sbd->sd_blocks_per_bitmap; + rbm->offset -= x * rbm->rgd->rd_sbd->sd_blocks_per_bitmap; + rbm->bi += x; return 0; } -- cgit v1.2.2