search for: nomerges

_mm_lfence was originally documented as a load fence. But in light of speculative execution vulnerabilities it has started being advertised as a way to prevent speculative execution. Current Intel Software Development Manual documents it as "Specifically, LFENCE does not execute until all prior instructions have completed locally, and no later instruction begins execution until LFENCE

Hi Craig, The review for the similar GPU problem is now up here: https://reviews.llvm.org/D85603 (+ some other patches on the Phabricator stack). >From a pragmatic perspective, the constraints added to program transforms there are sufficient for what you need. You'd produce IR such as: %token = call token @llvm.experimental.convergence.anchor() br i1 %c, label %then, label %else

...d by the kernel six times, so without adjusting the SCSI command timeout rsync (or anything in userspace) will be waiting three minutes after each error. Five seconds is long enough to exceed the USB bus reset cycle. Additionally, it is probably wise to set nr_requests to 1, readahead_kb to 0 and nomerges to 1 for the affected drive. Feedback on the patch is appreciated. Sincerely, Steve Thompson

On Fri, Nov 6, 2015 at 11:10 AM, Tim Northover <t.p.northover at gmail.com> wrote: > On 6 November 2015 at 11:00, Phil Tomson <phil.a.tomson at gmail.com> wrote: > > With 3.6 I get an unused argument warning with -enable-pie: > > > > $ clang -v -emit-llvm -enable-pie -O0 -S global_dat.c -o > > global_dat_x86_pie.ll > > Yes, it's an llc option not a

This patchset implements bio-based IO path for virito-blk to improve performance. Fio test shows it gives, 28%, 24%, 21%, 16% IOPS boost and 32%, 17%, 21%, 16% latency improvement for sequential read/write, random read/write respectively. Asias He (3): block: Introduce __blk_segment_map_sg() helper block: Add blk_bio_map_sg() helper virtio-blk: Add bio-based IO path for virtio-blk

This patchset implements bio-based IO path for virito-blk to improve performance. Fio test shows it gives, 28%, 24%, 21%, 16% IOPS boost and 32%, 17%, 21%, 16% latency improvement for sequential read/write, random read/write respectively. Asias He (3): block: Introduce __blk_segment_map_sg() helper block: Add blk_bio_map_sg() helper virtio-blk: Add bio-based IO path for virtio-blk

...ow = queue_show_nonrot, .store = queue_store_nonrot, }; static struct queue_sysfs_entry queue_zoned_entry = { - .attr = {.name = "zoned", .mode = S_IRUGO }, + .attr = {.name = "zoned", .mode = 0444 }, .show = queue_zoned_show, }; static struct queue_sysfs_entry queue_nomerges_entry = { - .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR }, + .attr = {.name = "nomerges", .mode = 0644 }, .show = queue_nomerges_show, .store = queue_nomerges_store, }; static struct queue_sysfs_entry queue_rq_affinity_entry = { - .attr = {.name = "rq_aff...

...ow = queue_show_nonrot, .store = queue_store_nonrot, }; static struct queue_sysfs_entry queue_zoned_entry = { - .attr = {.name = "zoned", .mode = S_IRUGO }, + .attr = {.name = "zoned", .mode = 0444 }, .show = queue_zoned_show, }; static struct queue_sysfs_entry queue_nomerges_entry = { - .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR }, + .attr = {.name = "nomerges", .mode = 0644 }, .show = queue_nomerges_show, .store = queue_nomerges_store, }; static struct queue_sysfs_entry queue_rq_affinity_entry = { - .attr = {.name = "rq_aff...

On 9/7/20 10:56 AM, Nicolai Hähnle wrote: > Hi Johannes and Atmn, > > On Sat, Sep 5, 2020 at 7:07 AM Johannes Doerfert via llvm-dev > <llvm-dev at lists.llvm.org> wrote: >>  > In any case, please explain the intended behavior of the attribute and >>  > the metadata upon inlining. >> >> The attribute will be attached to the caller upon

On 9/7/20 2:52 PM, Nicolai Hähnle wrote: > Hi Johannes, > > On Mon, Sep 7, 2020 at 6:51 PM Johannes Doerfert > <johannesdoerfert at gmail.com> wrote: >> On 9/7/20 10:56 AM, Nicolai Hähnle wrote: >>  > Hi Johannes and Atmn, >>  > >>  > On Sat, Sep 5, 2020 at 7:07 AM Johannes Doerfert via llvm-dev >>  > <llvm-dev at

...uct bio *bio) +int elv_merge(struct blk_queue_ctx *ctx, struct request **req, struct bio *bio) { + struct request_queue *q = ctx->queue; struct elevator_queue *e = q->elevator; struct request *__rq; int ret; + assert_spin_locked(&ctx->lock); + /* * Levels of merges: * nomerges: No merges at all attempted * noxmerges: Only simple one-hit cache try * merges: All merge tries attempted */ if (blk_queue_nomerges(q)) return ELEVATOR_NO_MERGE; /* * First try one-hit cache. */ - if (q->last_merge && elv_rq_merge_ok(q->last_merge, bio))...

...uct bio *bio) +int elv_merge(struct blk_queue_ctx *ctx, struct request **req, struct bio *bio) { + struct request_queue *q = ctx->queue; struct elevator_queue *e = q->elevator; struct request *__rq; int ret; + assert_spin_locked(&ctx->lock); + /* * Levels of merges: * nomerges: No merges at all attempted * noxmerges: Only simple one-hit cache try * merges: All merge tries attempted */ if (blk_queue_nomerges(q)) return ELEVATOR_NO_MERGE; /* * First try one-hit cache. */ - if (q->last_merge && elv_rq_merge_ok(q->last_merge, bio))...