On (01/29/15 15:35), Minchan Kim wrote: > > As you told, the data was not stable. > yes. fread test was always slower, and the rest was mostly slower. > Anyway, when I read down_read implementation, it's one atomic instruction. > Hmm, it seems te be better for srcu_read_lock which does more things. > srcu looks havier, agree. > But I guessed most of overhead are from [de]compression, memcpy, clear_page > That's why I guessed we don't have measurable difference from that. > What's the data pattern if you use iozone? by "data pattern" you mean usage scenario? well, I usually use zram for `make -jX', where X=[4..N]. so N concurrent read-write ops scenario. -ss > I guess it's really simple pattern compressor can do fast. I used /dev/sda > for dd write so more realistic data. Anyway, if we has 10% regression even if > the data is simple, I never want to merge it. > I will test it carefully and if it turns out lots regression, > surely, I will not go with this and send the original patch again. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>