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bda9c7d92f
seq_printf is costly. For each block device, 19 decimal values are yielded in /proc/diskstats via seq_printf. On a system with 16 logical block devices, profiling for open/read/close sequences shows seq_printf took ~75% samples of diskstats_show: diskstats_show(92.626% 2269372/2450040) seq_printf(76.026% 1725313/2269372) vsnprintf(99.163% 1710866/1725313) format_decode(26.597% 455040/1710866) number(19.554% 334542/1710866) memcpy_orig(4.183% 71570/1710866) ... srso_return_thunk(0.009% 148/1725313) part_stat_read_all(8.030% 182236/2269372) One million rounds of open/read/close /proc/diskstats takes: real 0m37.687s user 0m0.264s sys 0m32.911s On average, each sequence tooks ~0.032ms With this patch, most decimal values are yield via seq_put_decimal_ull, performance is significantly improved: real 0m20.792s user 0m0.316s sys 0m20.463s On average, each sequence tooks ~0.020ms, a ~37.5% improvement. Signed-off-by: David Wang <00107082@163.com> Link: https://lore.kernel.org/r/20241108054500.4251-1-00107082@163.com Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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| .. | ||
| partitions | ||
| badblocks.c | ||
| bdev.c | ||
| bfq-cgroup.c | ||
| bfq-iosched.c | ||
| bfq-iosched.h | ||
| bfq-wf2q.c | ||
| bio-integrity.c | ||
| bio.c | ||
| blk-cgroup-fc-appid.c | ||
| blk-cgroup-rwstat.c | ||
| blk-cgroup-rwstat.h | ||
| blk-cgroup.c | ||
| blk-cgroup.h | ||
| blk-core.c | ||
| blk-crypto-fallback.c | ||
| blk-crypto-internal.h | ||
| blk-crypto-profile.c | ||
| blk-crypto-sysfs.c | ||
| blk-crypto.c | ||
| blk-flush.c | ||
| blk-ia-ranges.c | ||
| blk-integrity.c | ||
| blk-ioc.c | ||
| blk-iocost.c | ||
| blk-iolatency.c | ||
| blk-ioprio.c | ||
| blk-ioprio.h | ||
| blk-lib.c | ||
| blk-map.c | ||
| blk-merge.c | ||
| blk-mq-cpumap.c | ||
| blk-mq-debugfs.c | ||
| blk-mq-debugfs.h | ||
| blk-mq-pci.c | ||
| blk-mq-sched.c | ||
| blk-mq-sched.h | ||
| blk-mq-sysfs.c | ||
| blk-mq-tag.c | ||
| blk-mq-virtio.c | ||
| blk-mq.c | ||
| blk-mq.h | ||
| blk-pm.c | ||
| blk-pm.h | ||
| blk-rq-qos.c | ||
| blk-rq-qos.h | ||
| blk-settings.c | ||
| blk-stat.c | ||
| blk-stat.h | ||
| blk-sysfs.c | ||
| blk-throttle.c | ||
| blk-throttle.h | ||
| blk-timeout.c | ||
| blk-wbt.c | ||
| blk-wbt.h | ||
| blk-zoned.c | ||
| blk.h | ||
| bounce.c | ||
| bsg-lib.c | ||
| bsg.c | ||
| disk-events.c | ||
| early-lookup.c | ||
| elevator.c | ||
| elevator.h | ||
| fops.c | ||
| genhd.c | ||
| holder.c | ||
| ioctl.c | ||
| ioprio.c | ||
| Kconfig | ||
| Kconfig.iosched | ||
| kyber-iosched.c | ||
| Makefile | ||
| mq-deadline.c | ||
| opal_proto.h | ||
| sed-opal.c | ||
| t10-pi.c | ||