https://bugzilla.kernel.org/show_bug.cgi?id=71641 --- Comment #9 from Chia-Hung Chang <fredchang.tc@xxxxxxxxx> --- (In reply to Theodore Tso from comment #8) > it's clear this isn't going to get performance up to 1.1 GB/s, but I'm > curious how much setting JBD2_NR_BATCH changes things at 512 and 1024 and > possibly even 2048. Once it no longer maters a difference, if you could do > another blktrace, and also gather lock_stat information, that would be > useful. > > To gather lock_stat information, enable CONFIG_LOCK_STAT, and then "echo 0 > > /proc/lock_stat" before you start the workload, and then capture the > output of /proc/lock_stat after you finish running your workload/benchmark. > > If you also regather numbers with lock_stat enabled on a stock 3.11 kernel > (and also get a /proc/lock_stat report from a stock 3.11 kernel, with and > without data=journal), that would be useful. > > If it turns out that there is some lock contention going on with some of the > jbd2 spinlocks, there are some patches queued for 3.15 that I may have to > ask you to try (which will mean going to something like 3.14-rc7 plus some > additional patches from the ext4 git tree). > > Thanks for your benchmarking! Thanks for your advice. With the same environment setting and 'dd' command, The benchmarks of JBD2_NR_batch with data=journal are showed as following, JBD2_NR_batch =64 ->386 MB/s JBD2_NR_batch =254 ->400MB/s JBD2_NR_batch =512 ->407MB/s JBD2_NR_batch =1024 with CONFIG_LOCK_STAT enable ->304MB/s JBD2_NR_batch =2048 ->440MB/s --------------------------- /proc/lock_stat report with data=journal data collected at the end of "dd" https://dl.dropboxusercontent.com/u/32959539/lock_stat_result data collected in the middle of "dd" execution https://dl.dropboxusercontent.com/u/32959539/lock_stat_result2 /proc/lock_stat report with data=ordered https://dl.dropboxusercontent.com/u/32959539/lock_stat_ordered ------------------------------ blktrace of JBD2_NR_batch =2048 with data=journal https://dl.dropboxusercontent.com/u/32959539/JBD2_NR_batch_2048.7z Please tell me if you need further information. -- You are receiving this mail because: You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
